125cc title leader Marc Marquez, who rode to seventh with a dislocated shoulder last time out at Brno, was back on top of the two-stroke timesheets during Friday practice at Indianapolis.

A session of plentiful P1 changes ended with Marquez, who had suffered a small fall from his Ajo Derbi after 13 minutes of the hour, holding a 0.151sec over nearest title rival Pol Espargaro, whom Marquez leads by 15 points in the standings.

Brno winner Nicolas Terol was third with Sandro Cortese fourth and Bradley Smith fifth on the second Bancaja Aprilia, and the final rider within one-second of Marquez.

Friday practice - Indianapolis:

1. Marquez (Derbi) 1m 49.452s
2. Espargaro (Derbi) +0.151s
3. Terol (Aprilia) +0.246s
4. Cortese (Derbi) +0.377s
5. Smith (Aprilia) +0.456s
6. Vazquez (Derbi) +0.787s
7. Koyama (Aprilia) +1.266s
8. Rabat (Aprilia) +1.290s
9. Webb (Aprilia) +1.293s
10. Salom (Aprilia) +1.351s