Bottas: Mercedes' season will be 'tricky' without downforce gains

The Monaco and Hungarian Grands Prix were Mercedes' weakest of the season, as Sebastian Vettel led Kimi Raikkonen in a Ferrari one-two in both races.

Bottas finished fourth in Monaco and third in Hungary, with team-mate Lewis Hamilton seventh and fourth respectively.

Mercedes team bosses have admitted its 'ugly' performance in Monaco enabled it to identify and resolve the weaknesses of its 2017 car.

Bottas believes the car has been improved but will only know for sure once the championship moves beyond the Belgian and Italian Grands Prix, where Mercedes is expected to be strong anyway.

"I really think the next at least two races on paper should be a bit better for us [than Hungary] compared to Ferrari," Bottas said. "But I think we've made some good progress.

"We definitely do have work to do, they are quick through the corners, and we need to work on that.

"We need to work on our maximum-downforce package, that's the main thing.

"There are still a lot of tracks to come that require a lot of downforce.

"Spa is more about efficiency, Monza is very low-downforce, then Singapore is about downforce again.

"We are really working hard and trying to get the car better, because if we don't make any progress, it's going to be a tricky season, for sure."

Bottas arrived at Mercedes as replacement for 2016 champion Nico Rosberg in the off-season.

He has scored two grand prix wins and has been on the podium in all but three races in 2017, which has allowed him to remain in touch with Vettel and Hamilton in the title race.

Bottas is 33 points behind Ferrari's championship leader Vettel in the drivers' standings, and has contributed to Mercedes leading Ferrari by 39 points in the constructors' championship.

He says he was hoping for even better results than that.

"I was hoping to be slightly better positioned in the championship, and also as a team I think," Bottas said.

"We are still looking good in the constructors', but we have had some difficult races for us, which is not ideal.

"For us as a team, only winning is good enough, that's always got to be the target. I think we definitely have work to do. I have work to do.

"There are still things I can improve, as long as I keep working with the team as we've been doing at this point of the year.

"I know the second half will be better for me, and my best performances are still on the way.

"I would say the first half has been average, because I always set targets very high, but obviously [there have been] some good moments as well."