Christian Horner on Saturday hinted strongly that Red Bull is still eying a supply of Mercedes engines for the 2010 season.
With speculation pointing at a buyout by the German manufacturer of current engine customer Brawn, it had been suggested that Red Bull might instead choose to stick with its Renault power plants.
But after qualifying at Monza, boss Horner told the German broadcaster RTL: "(Mercedes powered) Force India is in some unbelievable form, but there are six Mercedes engines in the top seven.
"For sure that is no coincidence," the Briton added. "Mercedes builds very good engines."
Also at Monza, Ross Brawn would not comment on the reports about Mercedes buying 75 per cent of his Brackley based team.
"I'm not going to comment on our specific plans, drivers, sponsors, they'll all be announced in due course.
"We're very comfortable with where we're going to be next year. That's as much as I would like to say," said Brawn.
