Mercedes' Valtteri Bottas was hoping to be closer to championship leader Sebastian Vettel after the first half of the 2017 campaign.
The Finn is currently third in the drivers' standings, 19 points behind team mate Lewis Hamilton but 33 points adrift from Vettel.
"I was hoping to be slightly better positioned in the championship, and also as a team I think," Bottas told Autosport.
"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."
While the 27-year-old believes he has settled in nicely at Mercedes, clinching his first two F1 wins this year, he also says he is still a work in progress with more speed to be unlocked.
"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," added Bottas.
"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."
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