Toto Wolff sees Ferrari and Red Bull once again as Mercedes' main opposition in 2018, but the boss of the German squad will be attentive to McLaren's performance next year.
The Silver Arrows team has been in charge of Formula 1 for the past four years, although Ferrari made serious inroads this season into the Manufacturer's dominance.
As McLaren faces a new dawn with engine partner Renault, Wolff says it would be wrong to rule out the Woking-based outfit given its will to return to the winner's circle.
"We mustn't discount anybody," Wolff told Formula1.com.
"Today, as it stands, it looks like Ferrari and Red Bull.
"I am curious to see where McLaren and Renault come out. I wouldn't write anybody off. The rules will stay the same so it could be a very competitive season."
If anything, a third rival to Mercedes stepping up to the mantle would be great for the sport and the fans, says Wolff.
"I guess we will see a fight between Mercedes, Ferrari and Red Bull Racing - and maybe McLaren-Renault will join us in the title fight. That is an exciting outlook for the fans"
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