Thomas Luthi finished both of Friday's practice sessions for the Catalunya Moto2 Grand Prix with a commanding advantage - despite tumbling in the afternoon session.

Luthi, who held a half-second advantage in morning practice, was sitting 0.861s clear of the field when he lowsided from his Interwetten Suter with eight minutes to go in the afternoon outing.

Unable to return in time, Luthi - winner last time out in Le Mans - nonetheless remained out of reach to the tune of 0.403s over Scott Redding. The Marc VDS rider set his best time on his penultimate lap and was in turn 0.4sec quicker than title leader Pol Espargaro (Pons Kalex).

Multiple Moto2 winner Andrea Iannone returned to the sharp end with fourth place for the Speed Master (Speed Up) squad, with Alex de Angelis dropping from second to fifth in the closing stages for Forward Racing (Suter).

Espargaro starts round five with a one point lead over countryman Marc Marquez. Marquez, who injured a finger in his race day fall last time at Le Mans, managed just twelfth place in both of Friday's sessions for Repsol Suter.

Friday practice (2):

1. Thomas Luthi SWI (Suter) 1m 46.768s
2. Scott Redding GBR (Kalex) 1m 47.171s
3. Pol Espargaro SPA (Kalex) 1m 47.598s
4. Andrea Iannone ITA (Speed Up) 1m 47.613s
5. Alex De Angelis RSM (Suter) 1m 47.629s
6. Takaaki Nakagami JPN (Kalex) 1m 47.697s
7. Johann Zarco FRA (MotoBI) 1m 47.787s
8. Randy Krummenacher SWI (Kalex) 1m 47.825s
9. Simone Corsi ITA (FTR) 1m 47.831s
10. Toni Elias SPA (Suter) 1m 47.851s
11. Bradley Smith GBR (Tech 3) 1m 48.100s
12. Marc Marquez SPA (Suter) 1m 48.171s
13. Esteve Rabat SPA (Kalex) 1m 48.179s
14. Ricard Cardus SPA (AJR) 1m 48.182s
15. Mika Kallio FIN (Kalex) 1m 48.233s