Martin Whitmarsh has candidly confessed that last weekend's Turkish Grand Prix in Istanbul was McLaren-Mercedes' 'worst' performance of the F1 2011 campaign to-date - but he insists the team will 'keep pushing' and 'turn it around as quickly as we can'.

After Lewis Hamilton had finally stopped defending F1 World Champion Sebastian Vettel in his tracks by overhauling the young German for Chinese Grand Prix glory in Shanghai three weeks earlier, hopes were high inside the Woking-based outfit that McLaren would be able to heap further pain upon Red Bull Racing in Turkey.

A raft of crucial new updates for the fast-improving MP4-26 added to that overriding sense of optimism - one strengthened by the team's one-two finish at Istanbul Park twelve months earlier - but following a loss of practice time due to rain and reliability issues, those development parts were never used in anger, and Hamilton ultimately took the chequered flag more than 40 seconds adrift of race-winner Vettel down in fourth place, with team-mate Jenson Button a further 20 seconds in arrears again back in sixth.

It was undeniably a case of being brought right back down to earth with a shattering bump, with Ferrari joining Red Bull in comprehensively outperforming McLaren - as Fernando Alonso rubbed salt into the wounds by finishing half-a-minute ahead of Hamilton - and team principal Whitmarsh blamed excessive tyre-wear caused by on-track battles and pit-stop delays for the poor result. Must do better next time out in Barcelona, the Englishman acknowledged.

"If you're in front and you're looking after your tyres and you're driving in that manner, it's a positive," he reflected of Vettel's peerless afternoon, speaking to SPEED.com. "Conversely, the fact is that Ferrari were up there giving Red Bull a tough time. They are doing a good job, they're very strong and - there's no secret here - we've got to improve our car at a faster rate. Fernando did a good job - congratulations to him. We'll make sure we try and jump ahead at the next race.

"We've had the mean average best pit-stops of everyone [in F1 2011], so then to have a couple of [bad ones] is disappointing. The fact is you're trying to spin a nut on very quickly, it cross threaded, he hauled [it] off, he went to get the second gun, he felt that was cross-threaded so he tried to put it on manually. It will always happen; you will always have, when you're trying to bang nuts on that fast, a situation where occasionally you have one cross-threaded.

"It was the worst [race] this season, but I've had worse in my career, and I'm sure we're going to have a lot better as the season goes on. I think we can turn around and we will turn it around as quickly as we can. We will bring an upgrade to Spain and keep pushing, as simple as that."