diff --git a/lib/internal/test_runner/reporter/spec.js b/lib/internal/test_runner/reporter/spec.js
index 16cbdf1d5aa901..7afd30aa563a0f 100644
--- a/lib/internal/test_runner/reporter/spec.js
+++ b/lib/internal/test_runner/reporter/spec.js
@@ -12,7 +12,6 @@ const {
   StringPrototypeRepeat,
 } = primordials;
 const assert = require('assert');
-const Transform = require('internal/streams/transform');
 const { inspectWithNoCustomRetry } = require('internal/errors');
 const { green, blue, red, white, gray, shouldColorize } = require('internal/util/colors');
 const { kSubtestsFailed } = require('internal/test_runner/test');
@@ -35,26 +34,24 @@ const symbols = {
   'arrow:right': '\u25B6 ',
   'hyphen:minus': '\uFE63 ',
 };
-class SpecReporter extends Transform {
-  #stack = [];
-  #reported = [];
-  #indentMemo = new SafeMap();
-  #failedTests = [];
 
-  constructor() {
-    super({ writableObjectMode: true });
-  }
+async function* specReporter(source) {
+  const stack = [];
+  const reported = [];
+  const indentMemo = new SafeMap();
+  const failedTests = [];
 
-  #indent(nesting) {
-    let value = this.#indentMemo.get(nesting);
+  function indent(nesting) {
+    let value = indentMemo.get(nesting);
     if (value === undefined) {
       value = StringPrototypeRepeat('  ', nesting);
-      this.#indentMemo.set(nesting, value);
+      indentMemo.set(nesting, value);
     }
 
     return value;
   }
-  #formatError(error, indent) {
+
+  function formatError(error, indent) {
     if (!error) return '';
     const err = error.code === 'ERR_TEST_FAILURE' ? error.cause : error;
     const message = ArrayPrototypeJoin(
@@ -64,7 +61,8 @@ class SpecReporter extends Transform {
       ), `\n${indent}  `);
     return `\n${indent}  ${message}\n`;
   }
-  #formatTestReport(type, data, prefix = '', indent = '', hasChildren = false, skippedSubtest = false) {
+
+  function formatTestReport(type, data, prefix = '', indent = '', hasChildren = false, skippedSubtest = false) {
     let color = colors[type] ?? white;
     let symbol = symbols[type] ?? ' ';
     const duration_ms = data.details?.duration_ms ? ` ${gray}(${data.details.duration_ms}ms)${white}` : '';
@@ -73,76 +71,76 @@ class SpecReporter extends Transform {
       // If this test has had children - it was already reported, so slightly modify the output
       return `${prefix}${indent}${color}${symbols['arrow:right']}${white}${title}\n`;
     }
-    const error = this.#formatError(data.details?.error, indent);
+    const error = formatError(data.details?.error, indent);
     if (skippedSubtest) {
       color = gray;
       symbol = symbols['hyphen:minus'];
     }
     return `${prefix}${indent}${color}${symbol}${title}${white}${error}`;
   }
-  #handleTestReportEvent(type, data) {
-    const subtest = ArrayPrototypeShift(this.#stack); // This is the matching `test:start` event
+
+  function handleTestReportEvent(type, data) {
+    const subtest = ArrayPrototypeShift(stack); // This is the matching `test:start` event
     if (subtest) {
       assert(subtest.type === 'test:start');
       assert(subtest.data.nesting === data.nesting);
       assert(subtest.data.name === data.name);
     }
     let prefix = '';
-    while (this.#stack.length) {
+    while (stack.length) {
       // Report all the parent `test:start` events
-      const parent = ArrayPrototypePop(this.#stack);
+      const parent = ArrayPrototypePop(stack);
       assert(parent.type === 'test:start');
       const msg = parent.data;
-      ArrayPrototypeUnshift(this.#reported, msg);
-      prefix += `${this.#indent(msg.nesting)}${symbols['arrow:right']}${msg.name}\n`;
+      ArrayPrototypeUnshift(reported, msg);
+      prefix += `${indent(msg.nesting)}${symbols['arrow:right']}${msg.name}\n`;
     }
     let hasChildren = false;
-    if (this.#reported[0] && this.#reported[0].nesting === data.nesting && this.#reported[0].name === data.name) {
-      ArrayPrototypeShift(this.#reported);
+    if (reported[0] && reported[0].nesting === data.nesting && reported[0].name === data.name) {
+      ArrayPrototypeShift(reported);
       hasChildren = true;
     }
     const skippedSubtest = subtest && data.skip && data.skip !== undefined;
-    const indent = this.#indent(data.nesting);
-    return `${this.#formatTestReport(type, data, prefix, indent, hasChildren, skippedSubtest)}\n`;
+    const _indent = indent(data.nesting);
+    return `${formatTestReport(type, data, prefix, _indent, hasChildren, skippedSubtest)}\n`;
   }
-  #handleEvent({ type, data }) {
+
+  for await (const { type, data } of source) {
     switch (type) {
       case 'test:fail':
         if (data.details?.error?.failureType !== kSubtestsFailed) {
-          ArrayPrototypePush(this.#failedTests, data);
+          ArrayPrototypePush(failedTests, data);
         }
-        return this.#handleTestReportEvent(type, data);
+        yield handleTestReportEvent(type, data);
+        break;
       case 'test:pass':
-        return this.#handleTestReportEvent(type, data);
+        yield handleTestReportEvent(type, data);
+        break;
       case 'test:start':
-        ArrayPrototypeUnshift(this.#stack, { __proto__: null, data, type });
+        ArrayPrototypeUnshift(stack, { __proto__: null, data, type });
         break;
       case 'test:stderr':
       case 'test:stdout':
-        return data.message;
+        yield data.message;
+        break;
       case 'test:diagnostic':
-        return `${colors[type]}${this.#indent(data.nesting)}${symbols[type]}${data.message}${white}\n`;
+        yield `${colors[type]}${indent(data.nesting)}${symbols[type]}${data.message}${white}\n`;
+        break;
       case 'test:coverage':
-        return getCoverageReport(this.#indent(data.nesting), data.summary, symbols['test:coverage'], blue, true);
+        yield getCoverageReport(indent(data.nesting), data.summary, symbols['test:coverage'], blue, true);
+        break;
     }
   }
-  _transform({ type, data }, encoding, callback) {
-    callback(null, this.#handleEvent({ type, data }));
-  }
-  _flush(callback) {
-    if (this.#failedTests.length === 0) {
-      callback(null, '');
-      return;
-    }
+  if (failedTests.length !== 0) {
     const results = [`\n${colors['test:fail']}${symbols['test:fail']}failing tests:${white}\n`];
-    for (let i = 0; i < this.#failedTests.length; i++) {
-      ArrayPrototypePush(results, this.#formatTestReport(
+    for (let i = 0; i < failedTests.length; i++) {
+      ArrayPrototypePush(results, formatTestReport(
         'test:fail',
-        this.#failedTests[i],
+        failedTests[i],
       ));
     }
-    callback(null, ArrayPrototypeJoin(results, '\n'));
+    yield results.join('\n');
   }
 }
 
-module.exports = SpecReporter;
+module.exports = specReporter;
diff --git a/test/parallel/test-runner-run.mjs b/test/parallel/test-runner-run.mjs
index b5c41b8ae925de..45df61cb6dcc86 100644
--- a/test/parallel/test-runner-run.mjs
+++ b/test/parallel/test-runner-run.mjs
@@ -76,12 +76,17 @@ describe('require(\'node:test\').run', { concurrency: true }, () => {
   });
 
   it('should be piped with spec', async () => {
-    const specReporter = new spec();
-    const result = await run({ files: [join(testFixtures, 'test/random.cjs')] }).compose(specReporter).toArray();
+    const result = await run({ files: [join(testFixtures, 'test/random.cjs')] }).compose(spec).toArray();
     const stringResults = result.map((bfr) => bfr.toString());
     assert.match(stringResults[0], /this should pass/);
     assert.match(stringResults[1], /tests 1/);
-    assert.match(stringResults[1], /pass 1/);
+    assert.match(stringResults[2], /suites 0/);
+    assert.match(stringResults[3], /pass 1/);
+    assert.match(stringResults[4], /fail 0/);
+    assert.match(stringResults[5], /cancelled 0/);
+    assert.match(stringResults[6], /skipped 0/);
+    assert.match(stringResults[7], /todo 0/);
+    assert.match(stringResults[8], /duration_ms \d+\.?\d*/);
   });
 
   it('should be piped with tap', async () => {