STUTTGART, Germany - Mercedes' motorsport director Toto Wolff has admitted Mercedes was disappointed by long-time partner McLaren's move to use Honda engines in 2015.Mercedes, current McLaren's engine partner, set up its own F1 team a few years ago, leaving the great British outfit with the prospect of a customer engine bill.But that will end after 2014 when Japanese automaker Honda returns to F1 after a six-year absence to rekindle with McLaren the famous and highly successful partnership of the 1980's and 90's.'IT'S UNPLEASANT'Mercedes, though focused on its works squad but still supplying McLaren and Force India, admitted it was disappointed to lose a great partner. Wolff told Speed Week: "It is not ideal when you lose a customer, especially when it's one such as McLaren which has been with Mercedes for so long and celebrated great successes with us."So of course it's unpleasant, but it's a decision they've taken. We also look forward to having another competitor in F1 - Honda is a top brand and, as the saying goes, competition is good for business." Wolff said Mercedes was not worried that its only other current customer engine partner, Force India, could also jump ship to Honda."No, because everyone has only a limited ability to supply customer teams," he explained.NEW PARTNER?"For us, it's three or four teams, and we're confident that in coming years we will have at least three (Mercedes-powered) teams in Formula 1," he said.That implies that Mercedes is now looking for a replacement for McLaren beyond 2014. Stay with Wheels24 for the 2013 Formula 1 season – fresh reports every day.