Red Bull boss Christian Horner challenges Mark Webber to keep on delivering in 2013

Red Bull boss Christian Horner has assured Mark Webber he will keep his seat with the World Champions if he keeps on delivering strong results and pushing Sebastian Vettel.

However, it's the performances of Webber when measured against those of Vettel which are likely to hold sway when Red Bull consider their options beyond 2013. "The difficulty for Mark is he is constantly judged against a young man in the other car who has achieved so much," commented Horner. "Mark's being constantly measured against a driver that is, in my view, the best of a generation and that makes it harder for him. But at the same time Mark measures the opportunity of being measured against the best. "He has also demonstrated on his day he can be unbeatable. Last year he drove very well, and if he can get off to a good start and build up some momentum this season that will be important for his campaign. "Above all, if we didn't think he could still do it then we wouldn't have taken him for another year with the team."