Rea pointed out that he has "never had a tyre feel like this", but added that he was delighted to have come second behind team-mate Tom Sykes in both races, and extend his lead atop the World Superbike standings to 101 points.
"I have no idea, I've never had a tyre feel like this all weekend," Rea, who has won eight out of 12 races this season, told reporters. "In the beginning of the race at almost every corner on the throttle it was like riding on ice. So it was really difficult to control but once I found a rhythm I understood how to get the best out of it."
The Ulsterman also lauded Kawasaki and the rest of his support staff for helping him register his best World Superbike finish at Donington Park.
"It is the best weekend we've ever had here so I'd like to thank Kawasaki for all its efforts here, with the two bikes' 1-2," he said. "Pere my crew chief told me that the championship points gap is in three figures, which I cannot believe. It is incredible, so we just need to keep doing the same."