diff --git a/bin/plugin/commands/performance.js b/bin/plugin/commands/performance.js
index 75ab95a4cc4a10..0d91947da80212 100644
--- a/bin/plugin/commands/performance.js
+++ b/bin/plugin/commands/performance.js
@@ -3,7 +3,7 @@
  */
 const fs = require( 'fs' );
 const path = require( 'path' );
-const { mapValues, kebabCase } = require( 'lodash' );
+const { mapValues } = require( 'lodash' );
 const SimpleGit = require( 'simple-git' );
 
 /**
@@ -83,6 +83,17 @@ const config = require( '../config' );
  * @property {number=} maxListViewOpen        Max time to open list view.
  */
 
+/**
+ * Sanitizes branch name to be used in a path or a filename.
+ *
+ * @param {string} branch
+ *
+ * @return {string} Sanitized branch name.
+ */
+function sanitizeBranchName( branch ) {
+	return branch.replace( /[^a-zA-Z0-9-]/g, '-' );
+}
+
 /**
  * Computes the average number from an array numbers.
  *
@@ -299,8 +310,8 @@ async function runPerformanceTests( branches, options ) {
 	const branchDirectories = {};
 	for ( const branch of branches ) {
 		log( `    >> Branch: ${ branch }` );
-		const environmentDirectory =
-			rootDirectory + '/envs/' + kebabCase( branch );
+		const sanitizedBranch = sanitizeBranchName( branch );
+		const environmentDirectory = rootDirectory + '/envs/' + sanitizedBranch;
 		// @ts-ignore
 		branchDirectories[ branch ] = environmentDirectory;
 		const buildPath = `${ environmentDirectory }/plugin`;
@@ -401,7 +412,8 @@ async function runPerformanceTests( branches, options ) {
 		for ( let i = 0; i < TEST_ROUNDS; i++ ) {
 			rawResults[ i ] = {};
 			for ( const branch of branches ) {
-				const runKey = `${ branch }_${ testSuite }_run-${ i }`;
+				const sanitizedBranch = sanitizeBranchName( branch );
+				const runKey = `${ sanitizedBranch }_${ testSuite }_run-${ i }`;
 				// @ts-ignore
 				const environmentDirectory = branchDirectories[ branch ];
 				log( `    >> Branch: ${ branch }, Suite: ${ testSuite }` );
diff --git a/bin/plugin/lib/utils.js b/bin/plugin/lib/utils.js
index 4a75437a60694e..c50094321710ca 100644
--- a/bin/plugin/lib/utils.js
+++ b/bin/plugin/lib/utils.js
@@ -33,6 +33,7 @@ function runShellScript( script, cwd, env = {} ) {
 					NO_CHECKS: 'true',
 					PATH: process.env.PATH,
 					HOME: process.env.HOME,
+					USER: process.env.USER,
 					...env,
 				},
 			},