diff --git a/packages/playwright-core/src/server/trace/recorder/tracing.ts b/packages/playwright-core/src/server/trace/recorder/tracing.ts
index 5f0bfb15df..2639aff91d 100644
--- a/packages/playwright-core/src/server/trace/recorder/tracing.ts
+++ b/packages/playwright-core/src/server/trace/recorder/tracing.ts
@@ -179,7 +179,12 @@ export class Tracing extends SdkObject implements InstrumentationListener, Snaps
       this._allocateNewTraceFile(this._state);
 
     this._fs.mkdir(path.dirname(this._state.traceFile));
-    const event: trace.TraceEvent = { ...this._contextCreatedEvent, title: options.title, wallTime: Date.now() };
+    const event: trace.TraceEvent = {
+      ...this._contextCreatedEvent,
+      title: options.title,
+      wallTime: Date.now(),
+      monotonicTime: monotonicTime()
+    };
     this._fs.appendFile(this._state.traceFile, JSON.stringify(event) + '\n');
 
     this._context.instrumentation.addListener(this, this._context);
diff --git a/packages/trace-viewer/src/traceModernizer.ts b/packages/trace-viewer/src/traceModernizer.ts
index 1ade445382..a2a987318c 100644
--- a/packages/trace-viewer/src/traceModernizer.ts
+++ b/packages/trace-viewer/src/traceModernizer.ts
@@ -388,9 +388,11 @@ export class TraceModernizer {
         result.push({ ...event, monotonicTime: 0, origin: 'library' });
         continue;
       }
-      // Take wall time from the first event.
+      // Take wall and monotonic time from the first event.
       if (!this._contextEntry.wallTime && event.type === 'before')
         this._contextEntry.wallTime = event.wallTime;
+      if (!this._contextEntry.startTime && event.type === 'before')
+        this._contextEntry.startTime = event.startTime;
       result.push(event);
     }
     return result;