Jenson Button says McLaren's current form is "embarrassing" after another weekend of struggle, this time at the Spanish Grand Prix in Barcelona
The 2009 world champion dropped from 14th to 17th at the start before finishing in eighth place, one place ahead of team-mate Sergio Perez.
"It's a little bit embarrassing because we're not doing a very good job at the moment," said the Somerset-born driver.
"We are doing everything we can. Thanks for the support from the fans."
McLaren are enduring one of their worst starts to the season in their recent history, with hopes of a first constructors' title since 1998 fading by the race.
The team are sixth in the standings, 102 points behind leader Red Bull after five races. Their best finish so far came in China in April, when Button was fifth.
In the drivers' championship, Button and Perez are 72 and 77 points respectively behind leader Sebastian Vettel in his Red Bull.
McLaren made major design changes to their car for 2013, while most of their rivals took a more evolutionary approach, but the new car has suffered from a lack of aerodynamic downforce.
"We've got a lot of work to do," added Button, 33, after the race in Barcelona, won by Fernando Alonso. "There's a lot of useful information to go through from the new parts on the car and we've got some other parts coming for Monaco, too."
Although Button was unable to challenge for the big points, he took some consolation from the way the team's strategy helped him rise from 17th after the first corner to eighth at the finish.
He added: "When we moved to the harder of the two tyre compounds after the first stop, the balance was much better. I overtook a Mercedes and beat some cars we didn't think we would. It's not fantastic, but to get through to eighth shows a good job by the team in terms of strategy."
