Aleix Espargaro powered the Suzuki to the top of the timesheets to complete a clean sweep of the opening free practice sessions at the Termas de Rio Hondo circuit in Argentina after heading FP2.

Espargaro quickly lapped eight tenths faster than he managed in FP1 to shoot to the top of the times before spots of rain began to fall, with marshals waving the rain flag at turn 1.

As the rain became heavier, only Monster Yamaha Tech 3's Bradley Smith and Aprilia rider Marco Melandri remained on track, with Smith lapping three seconds off the pace.

However, conditions quickly improved and the majority of riders were soon back out on track, with CWM LCR Honda's Cal Crutchlow climbing the order into fourth place behind Espargaro, Repsol Honda's Marc Marquez and Ducati rider Andrea Dovizioso.

With 15 minutes remaining, Smith was holding fifth place on the satellite M1 ahead of Andrea Iannone (Ducati), Stefan Bradl on the Forward Yamaha and world championship leader Valentino Rossi.

In a dramatic end to the session, Pol Espargaro on the Monster Yamaha Tech 3 machine swapped places at the top with his brother Aleix before Scott Redding put a cat amongst the pigeons on the Estrella Galicia 0,0 Marc VDS Honda, briefly hitting the top after fitting the extra hard rear tyre.

It was all change moments later with Austin winner Marquez taking over the number one spot with a lap in 1m 39.3s, but Espargaro hit back on the GSX-RR with a lap in 1m 38.7s.

In the closing seconds Iannone surged up the timesheets into second ahead of Marquez, with Crutchlow and Dovizioso next.

Movistar Yamaha's Jorge Lorenzo produced a late fast lap to complete the top six on the factory M1 ahead of Pol Espargaro and Redding, who is aiming to make amends this weekend after crashing out of the Austin MotoGP on the first lap.

Espargaro's fastest lap of 1m 38.776s put him more than half a second ahead of Iannone (1m 39.311s), with Marquez only 0.025s further behind.

Rossi ended the session in ninth place with a lap in 1m 39.947s, which left the Italian rider 1.171s down on Espargaro, while Smith eventually finished 12th quickest behind rookie Maverick Vinales.

American Nicky Hayden was the leading Open class rider in 14th place on the Power Electronics Aspar Honda ahead of AB Motoracing's Karel Abraham and Hector Barbera on the Avintia Ducati.

FP2:

1. Aleix Espargaro

2. Andrea Iannone

3. Marc Marquez

4. Cal Crutchlow

5. Andrea Dovizioso

6. Jorge Lorenzo

7. Pol Espargaro

8. Scott Redding

9. Valentino Rossi

10. Yonny Hernandez

11. Maverick Vi?ales

12. Bradley Smith

13.Danilo Petrucci

14. Nicky Hayden

15. Karel Abraham

16. Hector Barbera

17. Stefan Bradl

18. Eugene Laverty

19.Jack Miller

20. Alex De Angelis

21.Hiroshi Aoyama

22.Alvaro Bautista

23. Mike Di Meglio

24. Marco Melandri

25.Loris Baz