MotoGP title leader Jorge Lorenzo believes the scorching hot Catalunya weather will make Sunday's 25-lap race the hardest of the season so far.
Lorenzo will start round seven from his third consecutive pole position, the Spaniard rising to the top in the final ten minutes of the hour after working to improve his race set-up and gather as much information as possible about the two tyre compounds.
The Fiat Yamaha rider finished the session 0.364sec clear of nearest rival Casey Stoner (Ducati) and 0.546sec in front of nearest title rival Dani Pedrosa, who lines-up fourth for Repsol Honda.
"I'm really happy with this third pole position, it seems we're doing a very good job and it's very special to get it at my home round," said Lorenzo, who lives in nearby Barcelona and won the first Spaniard round of the year at Jerez.
"It was a hard session but finally I was able to do some quick laps at the end with the soft tyre. It is so hot here and I think it's easy to say that tomorrow will be the hardest race so far this season.
"I will have to concentrate extra hard in this weather and also make sure that my physical condition is the best it can be.
"The tyres are going to be very important and we still have to make a final choice; before the practice we thought we had chosen but we're not so sure now so we will have to make our final decision tomorrow after warm-up," added Lorenzo, winner of four of the six races this season.
Lorenzo's temporary team-mate Wataru Yoshikawa made an improvement of more than two seconds over his Friday time, but will still start 17th and last.
The Yamaha test rider lapped 3.7sec from Lorenzo but just 0.182sec from Honda test rider Kousuke Akiyoshi.
The two Japanese stand-ins are likely to race amongst themselves on Sunday.
"I think that I can improve even more tomorrow, even though the race will be very hard," he said. "I will do my best to stay in touch and use the time to gather as much information as possible, which can help Yamaha in future development."
"Wataru improved his lap time a lot today. It's very difficult for him here; it's a new track, it's very hot and he's been away from racing for a long time, so he's not used to pushing hard in a short time," added team-mate Davide Brivio. "He has made a big effort and is getting quicker, so tomorrow we will see what happens. We know he will try his very best."