Virgin hoping to retain Glock for 2011

The German has registered only four finishes in 10 races in 2010, with a best result of 18th.

But despite a difficult season, Wirth is confident that Glock is fully committed to the cause even though Renault is believed to be interested in his services for next year.

"We've got another year on the contract with Timo, but like anything in life everyone has got to want to carry on," Wirth told AUTOSPORT

"Timo understood that we were a new team and he wanted to be part of something that was growing going forward. That's why the Silverstone weekend was so important because it has hopefully shown him that we can do it."

Wirth added that being able to attract and keep hold of a driver who has three podium finishes to his name is a good sign of the team's long-term potential.

"We were so lucky to have a driver with his talent, ability and experience join us at his age," said Wirth. "It's up to us to try and deliver on that

Wirth also believes that Lucas di Grassi has been an impressive rookie this season despite only outqualifying Glock once in 10 attempts.

"I know I'm very biased, but I think he is looking good for rookie of the year if you look at his relative performance," said Wirth.

"He's coming into his own and doing a fantastic job. The disadvantage is that Lucas is naturally a bit heavier than Timo. For all of the new teams, weight is an issue so he's still got a disadvantage. It's to do with us and we're working very hard on it."

Wirth is hopeful that di Grassi will be able to run on the weight limit before the end of the European season with a raft of lightweight parts planned.