Mercedes F1 boss Toto Wolff says personnel defections from the manufacturer's HPP engine department to Red Bull Powertrains were to be expected as the two teams fight on another "battleground".
Red Bull is in the process of setting up its own engine department at Milton Keynes where it will bring Honda's engine program in-house from next season and develop its own power unit in the future.
Red Bull pulled off a major coup recently by poaching Mercedes HPP's head of engineering Ben Hodgkinson, while other high profile hirings, possibly also from Mercedes, are expected to follow.
Speaking ahead of this weekend's Portuguese GP, Wolff admitted to not being surprised by Red Bull's head-hunting activity.
"Well, I guess it was expected that this would happen," Wolff said. "This is just a battleground, such as the one off the track. And you need to acknowledge that.
"And the last few weeks was certainly very much a pulling on both sides of the rope! Which I enjoyed. It's part of the competition. So you need to take it as a sportsman and sportsmanship."
Wolff said that Red Bull Powertrains' hiring initiatives were consistent with a strategic approach that the Mercedes F1 boss says is understandably appropriate.
"I think the right strategic steps have been, as far as I can see, set in motion from Red Bull," added Wolff.
"I think they are going to a track with their own power unit and maybe with a new OEM joining in. And that's certainly intelligent.
"The arrangement that has been found with with Honda and carrying over the IP is also clever. And then it's clear that they're going to hire English engineers, because it's in the United Kingdom.
"And there is not a lot of companies that can probably provide those engineers, so absolutely understood what the strategy is."