Jorge Lorenzo apologised to his team and Yamaha after crashing out of the race lead in Sunday's Czech Republic Grand Prix at Brno.
Lorenzo came into round eleven having lost points to Rossi at the last five races, allowing the Italian to construct a healthy 25 point lead over his team-mate at the top of the standings.
But the young Spaniard looked in with an excellent chance of halting Rossi after running a superior pace in practice, then sticking with the Italian as the pair disappeared into the distance throughout the middle stages of Sunday's race.
However, exactly one lap after taking the lead from Rossi - and with five laps still to go - Lorenzo lost the front and crashed out for the second race in succession.
Inevitably, suggestions that Lorenzo cracked under the pressure will be raised, but the man himself simply labelled it as a 'mistake'.
“I got a bad start and had to get by some people, and then I just didn't have the same pace that I'd had all weekend. I was slower than in the practices and it really wasn't what I was expecting,” said Lorenzo's who set the fastest lap of the race on lap 16 of 22, but his 1min 56.670sec was only 0.024sec quicker than Rossi and slower than he'd managed in all four previous track sessions.
“Unfortunately for me Valentino was just as strong as he'd been all weekend and I had to push very, very hard to stay with him. Towards the end I began to close the gap and after I passed him I was doing everything to stay in front, but then I made a mistake and crashed.
“There's nothing more I can say except that I'm so sorry to the team and to Yamaha and I will do everything I can to make it up in America.”
Team manager Daniele Romagnoli indicated that the pressure of racing Rossi, who has beaten Lorenzo by less than 0.1sec twice so far this season, was the main factor in the fall.
“Of course Jorge's target today was to try to beat Valentino in order to close the gap in the standings and so he was doing everything he could. He got past him but Valentino was still very close behind, putting a lot of pressure on Jorge and unfortunately he made a mistake and crashed,” said the Italian.
Rather than shatter his confidence, Romagnoli believes Lorenzo will now become stronger.
“It will be another important lesson for him and we are confident that he will learn from it continue to be just as fast and to keep improving,” he said. “He's got many more races to show his potential so now we will get back to work with a day's testing tomorrow and make sure we're in the best shape possible for Indianapolis.”
Lorenzo is now 50 points behind Rossi with six rounds remaining.