Australian MotoGP star Casey Stoner says he is recovering from the stomach ailment which made him vomit twice into his helmet while racing in Spain.
The 2007 world champion continues to struggle with a mysterious illness which he said severely hampered his efforts in Catalunya.
He grabbed third but wasa long way off the pace of winner Valentino Rossi and Spaniard Jorge Lorenzo.
Stoner is preparing for this weekend's US Grand Prix after finishing third in the last race in Holland.
He's wary of his sickness but better prepared.
"We have come straight to America from Assen and there hasn't been much time to recover, although I do feel better already," Stoner said.
"What we learned from last weekend is not to underestimate the symptoms."
Stoner conceded last year's US GP to Rossi after an engrossing battle. He is out to show he can bounce back after struggling through the previous two rounds.
"We have had some setbacks over the past couple of races that have prevented us from showing our full potential," he said.
"We have done a lot of work on the bike and found a great set-up for the race on both occasions, but I have not been in good shape when it was the moment to take advantage of that work.
"We have the potential to challenge for a good result again but well wait until we get out on track and see how things shape up."
Rossi has broken out of a three-way tie to take the series lead but says he is not underestimating Lorenzo or Stoner.
"We have to try to relax as much as possible and recharge the batteries a little, because Laguna is always a tough weekend and often very hot," Rossi said.
"Last year I had a great battle with Stoner and for me it was for sure one of the turning points of the championship and a very important win. I have some good memories. I think this year it will be hard again because Lorenzo is in brilliant form and I am sure Stoner will also be back to his best.
"The championship is very open so we need to keep focus, get back to normal after Assen and try to get another good result this weekend."
