
Webber, though, put up a much improved display at the European Grand Prix and he rated his third-place finish as "probably the best of the season".
Horner agrees with Webber's sentiments and is delighted that he is starting to bridge the gap to his team-mate.
"It was Mark's best race of the season in terms of his performance on those tyres," Horner is quoted by Reuters as saying. "It's the closest he has been to Sebastian all season. He drove well this weekend. Nobody is taking anything for granted."
Horner is also hopeful that the Australian will continue to improve as he's finally coming to grips with the new Pirelli tyres.
"I hope he keeps building up the momentum from this weekend," he said.
"He's made no secret of the fact he's struggled more on these tyres than Sebastian. I think he's understanding them better now.
"If you look at the time difference between the guys during the race he was never more than four or five seconds away for 90 percent of the race, which is the best we've seen all year.
"He'll take a lot of confidence out of the weekend."
Source: Planet-F1