Max Verstappen says Red Bull's Formula 1 form is "still not good enough", as the team is still further away from Mercedes than he would like.
Verstappen's run of results - which includes the only non-Mercedes victory of 2019 so far in Austria - has lifted him to third in the drivers' standings, but he said reducing its deficit to Mercedes remained Red Bull's main aim despite its recent trend of beating Ferrari.
Pushed on what challenges he thought he will face in the coming races, he said: "Closing the gap to Mercedes. That is the biggest one I think.
"We want to win so that is our biggest challenge ahead, to try to close that gap."
Asked how far he felt Red Bull was from Mercedes, he replied: "Further than I would like.
"We are getting closer but it is still not good enough. We know that.
"We are working hard to try to close it."
Verstappen acknowledged that a series of updates that Red Bull has introduced have improved its car's performance, but he added it was hard to judge how the chassis compares to Mercedes' because the two teams often run different downforce levels.
"Sometimes we are running a bit less downforce, sometimes a bit more," he said.
"It depends on how your car is balanced as well, high speed or low speed, one track is high speed and another is low speed.
"Also in Silverstone we were running less downforce so automatically in the low-speed corners you lose a bit of grip as well.
"We were faster on the straights at Silverstone which was a bit odd, but it seemed to work the best for us."
Verstappen does believe, however, that more progress from Honda, and Red Bull applying lessons it has learned from this year's car, could result in a bigger step forward in form for 2020.
"At the end of the day second is always better than third, but we are here to win," he said.
"Of course we want to be in front of Ferrari, but we want to be there with Mercedes.
"This year at the moment we are trying to get the most out of the engine as well and learn from what we did wrong at the beginning of the season, or not as good compared to Mercedes and Ferrari.
"Hopefully next year we can fight for the wins all the time."