Martin Whitmarsh has admitted that running Sergio Perez alongside Jenson Button in 2013 represents the optimum pairing on offer to McLaren, even if he says the jury is still out on the Mexican's potential.

Much has been made of Perez's form since he was named as the replacement for Mercedes-bound Lewis Hamilton, with four non-scores following the single point he claimed in Singapore prompting suggestions that there were better candidates on the market overlooked by Whitmarsh and the McLaren management.

Nico Hulkenberg, Paul di Resta and Heikki Kovalainen were all rumoured to have been in the frame while post-signing mischief has even suggested that Perez's Sauber team-mate Kamui Kobayashi would have been a better bet, but Whitmarsh maintains that his 2013 line-up is as good as it could have been.

"We have the best possible line-up that was available to us," he said in an interview with Britain's Daily Mail newspaper, "I think it is quite interesting. Jenson is a very relaxed individual and comfortable in his own skin. He's a real gent. We say nice things about drivers but, in the case of Jenson, everyone knows that it is true.

"I think he will be very good with Sergio because Sergio has got a lot to learn. But, when they get to Australia on the track, he will want to beat Sergio and we have to make sure, and I believe, Sergio will want to beat Jenson and that's how we run our team, that's the dynamics that we enjoy."

Of the alternatives, Hulkenberg is headed to Sauber for 2013, with di Resta likely to stay put at Force India. Both Kovalainen and Kobayashi could yet end up out of a drive, but Whitmarsh insists that there were few thoughts of replacing Hamilton with another Briton when Perez was available.

"I know Paul very well and helped him out on a number of things so, from that perspective, yes [there is a link], but actually we are an international team," he insisted, "We are an international brand. We happen to have two great British drivers at the moment but, looking forward, we had two British drivers because they were the two best I could hire, and we've got a British and a Mexican because they are the best two I could hire for the upcoming season and that is where we are at.

Asked whether he had had cause to regret the deal with Perez given his form since the Mexican signed on the dotted line, Whitmarsh pointed to several factors before admitting that his new recruit is very much a work in progress.

"He has been driving a Sauber and no one knows how good that Sauber is," he noted, perhaps overlooking the fact that Perez finished second in both Malaysia and Italy, and third in Canada, "[Sergio] is very young, only the same age as when Lewis started in F1. He hasn't been wildly groomed, I would say, but, despite all of those things, he's been able to sparkle. In Monaco, last year, as a rookie, was the first time we started to monitor [him] and, since then, he has had some giant-killing podiums.

"He's got something, but we don't know whether that something is enough to be groomed into a world champion. I think it might be so therefore it is an interesting challenge.

"He is going to find a different world at McLaren. He will turn up in Australia next year with so much more pressure on his shoulders and that is something he has to be groomed to deal with.

"McLaren, since 1966, has won more than 25 per cent of the all the races in which it has competed in [and], if [we] turn up and we're not on the first two rows and not competing for the win, then ourselves and Ferrari get that pressure in the way that no other F1 team does. When Red Bull weren't competitive, no one was piling into them.

"So there is an added pressure to being a McLaren driver. He might think he understands it, but he doesn't...."