Lewis Hamilton's decision to leave McLaren is a "mistake", according to their team principal Martin Whitmarsh.
Hamilton has signed a three-year deal with Mercedes to replace Michael Schumacher from next season.
Whitemarsh says he wouldn't advise anyone to leave McLaren if they want to win.
He says McClaren could not have offered better financial or competitive incentives for the 27-year-old Briton to stay.
Hamilton's departure has prompted McLaren to sign Sauber driver Sergio Perez as his replacement.
The future for seven-time world champion Schumacher looks uncertain, with the German, 43, saying he is undecided whether to retire following his release by Mercedes.