Mo Farah's return to competitive action ended with defeat by club runner Ellis Cross at the Vitality London 10,000.
Farah was racing for the first time since failing to qualify for the Tokyo Olympics last June and he was unable to outkick 26-year-old Cross over the final stages.
Farah, 39, finished in 28 minutes and 44 seconds, a minute outside his best time on the road, and was non-committal afterwards about his plans for the rest of the season.
Speaking to the BBC, the four-time Olympic champion said: "Your body has to be ready. You have to be in the right frame of mind. You have to be able to compete with the guys.
"Today was a tough day. Ellis did really well to win here. But you've got to see where you are. At the minute I don't even know. You've got to take it race by race and let the body see what it can do. I'm not getting any younger, am I?"