diff --git a/packages/webpack-cli/lib/groups/BasicGroup.js b/packages/webpack-cli/lib/groups/BasicGroup.js
deleted file mode 100644
index cbf8a41806d..00000000000
--- a/packages/webpack-cli/lib/groups/BasicGroup.js
+++ /dev/null
@@ -1,57 +0,0 @@
-const GroupHelper = require('../utils/GroupHelper');
-const logger = require('../utils/logger');
-const { core, groups } = require('../utils/cli-flags');
-
-class BasicGroup extends GroupHelper {
-    constructor(options) {
-        super(options);
-        this.WEBPACK_OPTION_FLAGS = core
-            .filter((coreFlag) => {
-                return coreFlag.group === groups.BASIC_GROUP;
-            })
-            .reduce((result, flagObject) => {
-                result.push(flagObject.name);
-                if (flagObject.alias) {
-                    result.push(flagObject.alias);
-                }
-                return result;
-            }, []);
-    }
-    resolveFlags() {
-        const { args } = this;
-        if (!args) return;
-        const { outputOptions, options } = this.opts;
-        Object.keys(args).forEach((arg) => {
-            if (this.WEBPACK_OPTION_FLAGS.includes(arg)) {
-                outputOptions[arg] = args[arg];
-            }
-            // TODO: to add once webpack bundle analyzer is installed, which is not at the moment
-            // if (arg == 'analyze') {
-            // const { BundleAnalyzerPlugin } = require('webpack-bundle-analyzer');
-            // this.opts.options.plugins = [new BundleAnalyzerPlugin()];
-            // }
-            if (arg === 'devtool') {
-                options.devtool = args[arg];
-            }
-            if (arg === 'name') {
-                options.name = args[arg];
-            }
-            if (arg === 'watch') {
-                options.watch = true;
-            }
-            if (arg === 'entry') {
-                options[arg] = this.resolveFilePath(args[arg], 'index.js');
-                if (options[arg].length === 0) {
-                    logger.error('\nError: you provided an invalid entry point.');
-                }
-            }
-        });
-    }
-
-    run() {
-        this.resolveFlags();
-        return this.opts;
-    }
-}
-
-module.exports = BasicGroup;
diff --git a/packages/webpack-cli/lib/groups/basicResolver.js b/packages/webpack-cli/lib/groups/basicResolver.js
new file mode 100644
index 00000000000..f4e548f7ae6
--- /dev/null
+++ b/packages/webpack-cli/lib/groups/basicResolver.js
@@ -0,0 +1,40 @@
+const { core, groups } = require('../utils/cli-flags');
+
+const WEBPACK_OPTION_FLAGS = core
+    .filter((coreFlag) => {
+        return coreFlag.group === groups.BASIC_GROUP;
+    })
+    .reduce((result, flagObject) => {
+        result.push(flagObject.name);
+        if (flagObject.alias) {
+            result.push(flagObject.alias);
+        }
+        return result;
+    }, []);
+
+function resolveArgs(args) {
+    const finalOptions = {
+        options: {},
+        outputOptions: {},
+    };
+    Object.keys(args).forEach((arg) => {
+        if (WEBPACK_OPTION_FLAGS.includes(arg)) {
+            finalOptions.outputOptions[arg] = args[arg];
+        }
+        if (arg === 'devtool') {
+            finalOptions.options.devtool = args[arg];
+        }
+        if (arg === 'name') {
+            finalOptions.options.name = args[arg];
+        }
+        if (arg === 'watch') {
+            finalOptions.options.watch = true;
+        }
+        if (arg === 'entry') {
+            finalOptions.options[arg] = args[arg];
+        }
+    });
+    return finalOptions;
+}
+
+module.exports = resolveArgs;
diff --git a/packages/webpack-cli/lib/utils/GroupHelper.js b/packages/webpack-cli/lib/utils/GroupHelper.js
index 18d1acb533d..e5e802f28ae 100644
--- a/packages/webpack-cli/lib/utils/GroupHelper.js
+++ b/packages/webpack-cli/lib/utils/GroupHelper.js
@@ -1,5 +1,3 @@
-const { resolve, join } = require('path');
-const { existsSync } = require('fs');
 const { arrayToObject } = require('../utils/arg-utils');
 
 class GroupHelper {
@@ -12,36 +10,6 @@ class GroupHelper {
         this.strategy = undefined;
     }
 
-    resolveFilePath(filename = '', defaultValue) {
-        if (filename && Array.isArray(filename)) {
-            return filename.map((fp) => this.resolveFilePath(fp, defaultValue)).filter((e) => e);
-        }
-        if (filename && !filename.includes('.js')) {
-            filename = filename + '.js';
-        }
-        if (defaultValue && !defaultValue.includes('.js')) {
-            defaultValue = defaultValue + '.js';
-        }
-        let configPath;
-        const predefinedConfigPath = filename ? resolve(process.cwd(), filename) : undefined;
-        const configPathExists = predefinedConfigPath ? existsSync(predefinedConfigPath) : undefined;
-
-        if (!configPathExists) {
-            const LOOKUP_PATHS = [`${filename}`, `src/${filename}`, ...(defaultValue ? [defaultValue, `src/${defaultValue}`] : [])];
-
-            if (filename) {
-                LOOKUP_PATHS.unshift(filename);
-            }
-            LOOKUP_PATHS.forEach((p) => {
-                const lookUpPath = join(process.cwd(), ...p.split('/'));
-                if (existsSync(lookUpPath) && !configPath) {
-                    configPath = lookUpPath;
-                }
-            });
-        }
-        return configPathExists ? predefinedConfigPath : configPath;
-    }
-
     run() {
         throw new Error('You must implement the "run" function');
     }
diff --git a/packages/webpack-cli/lib/webpack-cli.js b/packages/webpack-cli/lib/webpack-cli.js
index 8f08ae88a9d..17a7d0646e9 100644
--- a/packages/webpack-cli/lib/webpack-cli.js
+++ b/packages/webpack-cli/lib/webpack-cli.js
@@ -1,4 +1,7 @@
+const path = require('path');
+const { existsSync } = require('fs');
 const { options } = require('colorette');
+const webpackMerge = require('webpack-merge');
 const GroupHelper = require('./utils/GroupHelper');
 const handleConfigResolution = require('./groups/ConfigGroup');
 const resolveMode = require('./groups/resolveMode');
@@ -6,7 +9,7 @@ const resolveStats = require('./groups/resolveStats');
 const resolveOutput = require('./groups/resolveOutput');
 const { Compiler } = require('./utils/Compiler');
 const { groups, core } = require('./utils/cli-flags');
-const webpackMerge = require('webpack-merge');
+const basicResolver = require('./groups/basicResolver');
 const { toKebabCase } = require('./utils/helpers');
 const argParser = require('./utils/arg-parser');
 const { outputStrategy } = require('./utils/merge-strategies');
@@ -17,16 +20,6 @@ class WebpackCLI extends GroupHelper {
         this.groupMap = new Map();
         this.args = {};
         this.compilation = new Compiler();
-        this.defaultEntry = 'index';
-        this.possibleFileNames = [
-            `./${this.defaultEntry}`,
-            `./${this.defaultEntry}.js`,
-            `${this.defaultEntry}.js`,
-            this.defaultEntry,
-            `./src/${this.defaultEntry}`,
-            `./src/${this.defaultEntry}.js`,
-            `src/${this.defaultEntry}.js`,
-        ];
         this.compilerConfiguration = {};
         this.outputConfiguration = {};
     }
@@ -106,11 +99,6 @@ class WebpackCLI extends GroupHelper {
     resolveGroups() {
         for (const [key, value] of this.groupMap.entries()) {
             switch (key) {
-                case groups.BASIC_GROUP: {
-                    const BasicGroup = require('./groups/BasicGroup');
-                    this.basicGroup = new BasicGroup(value);
-                    break;
-                }
                 case groups.ADVANCED_GROUP: {
                     const AdvancedGroup = require('./groups/AdvancedGroup');
                     this.advancedGroup = new AdvancedGroup(value);
@@ -217,11 +205,13 @@ class WebpackCLI extends GroupHelper {
      * @returns {void}
      */
     _handleDefaultEntry() {
-        if (!this.basicGroup) {
-            const BasicGroup = require('./groups/BasicGroup');
-            this.basicGroup = new BasicGroup();
+        let defaultEntry;
+        const rootIndexPath = path.resolve('index.js');
+        if (existsSync(rootIndexPath)) {
+            defaultEntry = './index.js';
+        } else {
+            defaultEntry = './src/index.js';
         }
-        const defaultEntry = this.basicGroup.resolveFilePath(null, 'index.js');
         const options = { entry: defaultEntry };
         this._mergeOptionsToConfiguration(options);
     }
@@ -240,7 +230,7 @@ class WebpackCLI extends GroupHelper {
             .then(() => this._baseResolver(resolveMode, parsedArgs, this.compilerConfiguration))
             .then(() => this._baseResolver(resolveOutput, parsedArgs, {}, outputStrategy))
             .then(() => this._handleCoreFlags())
-            .then(() => this._handleGroupHelper(this.basicGroup))
+            .then(() => this._baseResolver(basicResolver, parsedArgs))
             .then(() => this._handleGroupHelper(this.advancedGroup))
             .then(() => this._baseResolver(resolveStats, parsedArgs))
             .then(() => this._handleGroupHelper(this.helpGroup));
diff --git a/test/entry/flag-entry/entry-with-flag.test.js b/test/entry/flag-entry/entry-with-flag.test.js
index 0fb810f469e..1f335734f3f 100644
--- a/test/entry/flag-entry/entry-with-flag.test.js
+++ b/test/entry/flag-entry/entry-with-flag.test.js
@@ -5,6 +5,23 @@ const { stat, readFile } = require('fs');
 const { resolve } = require('path');
 
 describe('entry flag', () => {
+    it('should resolve the path to src/index.cjs', (done) => {
+        const { stderr, stdout } = run(__dirname, ['--entry', './src/index.cjs', '-o', './dist/'], false);
+        expect(stderr).toBeFalsy();
+        expect(stdout).toBeTruthy();
+
+        stat(resolve(__dirname, './dist/main.js'), (err, stats) => {
+            expect(err).toBe(null);
+            expect(stats.isFile()).toBe(true);
+            done();
+        });
+        readFile(resolve(__dirname, './dist/main.js'), 'utf-8', (err, data) => {
+            expect(err).toBe(null);
+            expect(data).toContain('Kazuya Miyuki');
+            done();
+        });
+    });
+
     it('should load ./src/a.js as entry', (done) => {
         const { stderr, stdout } = run(__dirname, ['--entry', './src/a.js']);
         expect(stderr).toBeFalsy();
@@ -40,7 +57,9 @@ describe('entry flag', () => {
     });
 
     it('should throw error for invalid entry file', () => {
-        const { stderr } = run(__dirname, ['--entry', './src/test.js']);
-        expect(stderr).toContain('Error: you provided an invalid entry point.');
+        const { stdout, stderr, exitCode } = run(__dirname, ['--entry', './src/test.js']);
+        expect(stdout).toContain("Module not found: Error: Can't resolve");
+        expect(exitCode).toEqual(1);
+        expect(stderr).toBeFalsy();
     });
 });
diff --git a/test/entry/flag-entry/src/index.cjs b/test/entry/flag-entry/src/index.cjs
new file mode 100644
index 00000000000..f96f188d697
--- /dev/null
+++ b/test/entry/flag-entry/src/index.cjs
@@ -0,0 +1 @@
+console.log('Kazuya Miyuki');
diff --git a/test/zero-config/entry-absent/zero-config.test.js b/test/zero-config/entry-absent/zero-config.test.js
index 9acc630d895..34f65e83de9 100644
--- a/test/zero-config/entry-absent/zero-config.test.js
+++ b/test/zero-config/entry-absent/zero-config.test.js
@@ -4,7 +4,7 @@ describe('Zero Config tests', () => {
     it('runs when config and entry are both absent', () => {
         const { stdout, stderr } = run(__dirname, [], false);
         // Entry file is absent, should log the Error from the compiler
-        expect(stdout).toContain("Error: Can't resolve './src'");
+        expect(stdout).toContain("Error: Can't resolve './src/index.js'");
         expect(stderr).toBeFalsy();
     });
 });