Nobody could get within 1.1s of Marc Marquez during Friday MotoGP practice for his home round at Aragon.

While the world champion's morning soft-tyre stunner stood unopposed, it wasn't a perfect day for the Repsol Honda rider, who fell during the afternoon.

But even that tumble served a purpose, Marquez deliberately putting himself at 'risk' in order to gauge the suitability of the hard-front tyre.

"We are arriving from two difficult circuits for us, Silverstone and Misano, where we were still fighting for victory and I already said yesterday that this circuit with its left corners, and layout that I like, normally suits me," Marquez said of his dominant speed.

"I went out and from the beginning I found the correct lines, the correct braking points and even on the third run I was able to do a good time attack.

"I got a good slipstream along the back straight from Oliveira and this helped a little bit. But the target was a '47 low, so in the end '46 high was a good lap time.

"The feeling was great, from the second run. For you to understand, I used the same set-up from the first run in the morning to the last run in the afternoon."

Friday's strategy of a morning time attack was in stark contrast to Marquez's usual plan of sticking with used during day one. The catalyst for the change was a gloomy weather forecast for Saturday.

"Tomorrow the forecast looks like it will rain and FP3 will be wet," Marquez said. "Our strategy was first of all to analyse the tyres from last year and this year. Then we predicted that the tyres we want are either the hard or soft rear.

"For this reason I started directly with the hard and it was a good option. Then I felt ready on the second run to do a time attack. We had already spoken about this with Santi [crew chief] yesterday.

"Why wait until the afternoon? If you feel ready in the morning it was Plan A, the perfect plan, because then in the afternoon the plan was to work with used tyres and try to analyse which was better between the soft and hard rear tyres."

However, it would be the front tyre that proved Marquez's undoing at Turn 8 during FP2.

"I knew and the team knew I had a very big chance to crash on the afternoon," Marquez said. "I tried the hard-front tyre because looks like Sunday's conditions will be similar to today, so I said to the team 'If I have some warning then I prefer to have it this afternoon than on Sunday'.

"The first run was okay, then on the second run on the downhill just I lose the front. With the hard front you have less grip on the edge and I touched the white line a little.

"But as I said to the team, I prefer to have the warning this afternoon than in the race. Okay, it's not the best way to try, but it's the best way to choose the correct option for us in the race."

The lesson Marquez learned from the fall is that front tyre choice will be dependent on temperature.

"We also had the hard option to use in Misano, which was very warm but [the tyre] was not working. Here it looks like there is better grip on the track but less temperature," explained Marquez, who holds a 93 point lead over Ducati's Andrea Dovizioso.

"So we were on the limit but we tried to understand where the limit was. Now we understand the limit is the temperature. If it's colder we cannot use it, if it's warmer we can."

Marquez's team-mate Jorge Lorenzo was 20th on his return to the circuit where his injury woes began one year ago.

“We struggled with the feeling today and I was hoping to be more competitive after our stronger start in Misano," Lorenzo said. "In the afternoon I was able to improve a bit, but still I am looking to close the gap more.

"Sadly it looks like it will rain tomorrow which makes it a little harder for us as we will have less time to set up the bike but I will be able to do some running in the wet.”