Czech Grand Prix winner Cal Crutchlow celebrated his maiden MotoGP victory in Brno on Sunday, but the British rider thought Valentino Rossi was going to catch him.
Crutchlow qualified 10th on the grid but a superb ride, coupled with a faultless strategy, helped him to work his way through the field.
The 30-year-old hit the front with a handful of laps to go and never looked back despite pressure from Rossi, who finished second, while championship leader Marc Marquez was third.
"This is no joke, I looked up at the big screen and I saw Valentino coming, or who I thought was Valentino - but I actually think it was Hector [Barbera]," Crutchlow said after becoming the first Briton to win a premier class race in 35 years.
"I thought, 'OK, I have to go now because I'm in trouble'. I didn't know if Vale had the hard front tyre, so I started to push a little and then I saw the gap going up. It was one and a half seconds and then a few laps later it was four seconds.
"With four laps to go, I nearly had a crash in turn 10 because I changed to sixth gear when normally we would keep fifth gear and then I didn't stop and I thought, 'oh no'.
"Then I said, 'OK just keep calm' and after that I was just cruising around."
Conditions made riding tricky with a wet track and spots of rain, which Crutchlow accepted played a part in the LCR Honda team's surprise win.
"I know from many years of racing the rain is quite a leveller of rider and machinery," the Briton said.
"We know in MotoGP it's difficult to win on a satellite machine and we take our chances when we can."