diff --git a/ui/src/ui/control-ui-performance.test.ts b/ui/src/ui/control-ui-performance.test.ts
index 52b9ab6e799..6812b57c2dc 100644
--- a/ui/src/ui/control-ui-performance.test.ts
+++ b/ui/src/ui/control-ui-performance.test.ts
@@ -70,8 +70,13 @@ describe("recordControlUiPerformanceEvent", () => {
     }
 
     expect(host.eventLogBuffer).toHaveLength(250);
-    expect(host.eventLogBuffer[0]?.payload).toEqual({ i: 259 });
-    expect(host.eventLogBuffer.at(-1)?.payload).toEqual({ i: 10 });
+    const [newestEvent] = host.eventLogBuffer;
+    const oldestEvent = host.eventLogBuffer.at(-1);
+    if (!newestEvent || !oldestEvent) {
+      throw new Error("Expected bounded performance event buffer entries");
+    }
+    expect(newestEvent.payload).toEqual({ i: 259 });
+    expect(oldestEvent.payload).toEqual({ i: 10 });
   });
 });