Formula One champions Red Bull expect Mark Webber to be back up to speed in Malaysia this weekend after modifications to his car, team principal Christian Horner said on Monday.

While champion Sebastian Vettel was dominant from pole position in the Australian season-opener on March 27, his team mate Webber qualified only third and came home fifth overall with a considerable gap in performance between the two.

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"We've found, on a post-mortem of the event, a few things on Mark's car, a few things set-up wise, that certainly wouldn't have helped," Horner told reporters after a visit to see Silverstone circuit's new pit and paddock complex.

"All those elements have been changed for Malaysia, where we expect the two of them to be much closer together," added the Briton.

"There was no single issue that we could fingerpoint. There's elements that weren't right, and the difference that we've seen between the drivers during the course of the weekend was bigger than it's ever been and not right, so for sure they would have contributed."

Horner said he knew nothing about a report in the Sydney Morning Herald last month that an over-enthusiastic fan had intruded into the Red Bull garage before qualifying in Melbourne and broken a key aerodynamic component while leaning against it for a photograph.

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Webber, 34, had said earlier in a column in Australia's Daily Telegraph newspaper that he was little closer to understanding why his car was so much slower than Vettel's at Albert Park.

"More than anything, I struggled with a lack of grip. That affected the longevity of my Pirelli tyres because the degradation was much higher on my car than on Seb's," he said.

The second race of the season takes place at Sepang this weekend and Webber said Vettel's clear superiority over the field in the opener was also a positive for him.

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"Seb's pace proved that Red Bull Racing have built another great car this season and we both had impeccable reliability," he wrote.

Horner said Sepang would be a different challenge.

"It's a different kind of track and there's a few other factors, like the weather" he said.

"A couple of years ago we saw a big downpour that affected the outcome of the race and it's something you have always got to be ready for. It affected qualifying last year and we benefited from that.

"It's important that we are on our toes this weekend to make sure that we are on top of all the conditions and obviously the tyres.

"It's a bigger workout for the tyres as well in Malaysia, the conditions are going to be a lot hotter and it will stress the tyres a lot more. But I think they should cope with that without any issue."