Lewis Hamilton believes Mercedes may have it all their own way this season as both Ferrari and Red Bull are looking "quite strong."
Last year, the first under the 1.6-litre turbocharged V6 rules, Mercedes dominated the Championship.
Romping away with 16 of the 19 grands prix wins and both World titles, it was all about Mercedes.
This year, though, it is potentially shaping up to be a different story.
Ferrari have shown improved pace during pre-season testing while Red Bull were quickest on Day Two at Barcelona.
And although Hamilton says he's just focused on his own programme, the Brit admits those two could yet pose a threat to Mercedes.
"I've not been looking at the others. Maldonado was quick but I'm sure everyone was on different tyres, different fuel loads," he told reporters.
"I anticipate Ferrari look quite strong, similar to Red Bull, but I don't really know where we are amongst those.
"I think we'll maybe have a little bit of a better understanding next week.
"It's like juggling blind, but that's what I love about this sport; I don't really know what's to come.
"I anticipate a harder fight this year, that's what I'm anticipating."