Valtteri Bottas was celebrating second place on the podium this weekend at the Spanish Grand Prix. However, the Finn is worried that Mercedes' apparent resurgence at the Circuit de Barcelona-Catalunya may prove short-lived.
He admitted that he feared the team's rivals might have the upper hand in two weeks' time in Monaco, where Mercedes has traditionally struggled.
"Honestly I think Monaco is going to be difficult for us," he said after Sunday's race.
"As we saw last year, we think Red Bull is going to be really strong, and Ferrari was on pole last year.
"So it's going to be difficult, but we need to keep working hard and believing that we can improve things."
By contrast, the track at Barcelona is much better suited to the W09 - as today's dominant performance from Lewis Hamilton demonstrated. The only glitch for Mercedes was when Sebastian Vettel managed to slipstream past Bottas for second place into turn 1.
The team attempted to jump the Ferrari during the first round of pit stops, but that didn't work either. Bottas feared he wouldn't be able to do anything about the situation and was resigned to finishing in third.
"I was in a difficult situation after the first stint because I was stuck behind Sebastian," he said. "We knew that we had a strong car with a lot of pace and I think that we were quicker, but it is so hard to overtake here at this track.
"It was going to be tough being behind Sebastian all the time. But they [Ferrari] decided to stop again during the VSC and we didn't, which was the right decision.
"In the end it was difficult because I did nearly 45 laps with the medium!" he said, adding that one-stopping had never been the team's original strategy.
"I never believed we can do a one-stop," he said. "Honestly before the race we expected one stop was not going to be possible - at least to do the race quickly with one stop.
"But when we saw the tyres were holding up better than expected, we changed our strategy.
"The 1-2 we got today was definitely down to the decisions the team made during the race," he suggested. "Really reactive decision from the team."
While a podium is always a good outcome, it doesn't make up for the win that Bottas lost out on in Baku when he suffered a late puncture while leading the Azerbaijan Grand Prix.
"Well, of course I wanted to fight for the win of the race today. But as a team it's all a good race," he said. "It's great to get a lot of points for the team today.
"I think as a team this weekend we've been perfect. We just need to continue like that, and for me also the wins will come."