SILVERSTONE, England, July 3 (Reuters) - Formula One champions McLaren are waiting on Mercedes' latest engine upgrade to push them closer to the front, possibly as soon as this month's Belgian Grand Prix, boss Zak Brown said on Friday.
The team, with Britain's reigning champion Lando Norris and Australian Oscar Piastri, are currently third overall and far behind the Mercedes factory team and Ferrari.
"We have some work to do. We'll catch up," the American said at the British Grand Prix. "I think we'll be winning races this year, so I'm quite optimistic for the future."
Mercedes have so far won seven of eight grands prix and Ferrari, with Lewis Hamilton, the other, but Brown predicted McLaren and Red Bull would also be winners before the end of the year.
Mercedes have also been on pole in all the races.
McLaren won both titles last season as a customer team, buying in the same Mercedes engines as used by the works outfit and others.
"We just need to get some more development on the car, we need to get the current Mercedes engine," said Brown. "We're the only ones without the new engine, that will be coming for (to) us shortly."
"Any time you have performance that you know is coming but you don't have it on your car, you want to get it as quickly as possible," added Brown, who explained that McLaren were still working through their existing engine sequences and it was just a matter of timing.
Others had the latest version because of issues, as in the case of Carlos Sainz who needed an engine change at Williams, or different arrangements.
"You want it as quickly as you can but you need to run the cycles through the engines, obviously you can move things in and out, but we will want to see them hopefully next race," said Brown.
He predicted the next couple of races in Europe would show the team taking a step forward.
McLaren are one of four teams using Mercedes engines -- Mercedes F1, Renault-owned Alpine and Williams being the others.
Brown said McLaren needed to make their car more driveable and optimise the power unit.
(Reporting by Alan Baldwin; Editing by Toby Chopra)
