Valentino Rossi's historical problems with rear grip on high temperature circuits reared their head again today at the Jerez MotoGP round.

After testing well on Wednesday in cooler conditions, the Monster Yamaha man could only muster 13th on the combined free practice timesheet and is two-tenths off a Q2 place.

Rossi is at a loss for what to do as team-mate Maverick Vinales is suffering no such issues and neither are satellite riders Fabio Quartararo and Franco Morbidelli, who were fastest this afternoon with track temperatures reaching 56°C.

"It was a difficult day. This morning was already not fantastic, but this afternoon it got worse," admitted Rossi.

"I'm struggling with the rear grip because, unfortunately, we have a tyre temperature problem, and in this heat we are suffering a lot. In the morning it's cooler, so that's a bit better.

"In the afternoon we lose a lot, so I'm not very fast. We need to work, and we need to improve the bike's balance to try to be more competitive.

"Sincerely, I don't know how we will improve this, but we have to find something, because tomorrow morning it will be very important to try to stay in the top 10 and go straight into Q2."