Robert Kubica has warned against over-optimism following a stunning start to life with Renault that has even caught him by surprise.

The usual suspects from Red Bull, McLaren, Ferrari and Mercedes occupy eight of the top nine positions in the drivers' standings, with the odd one out being Kubica.

Following the Pole's much-deserved third place in the Monaco Grand Prix 10 days ago, Kubica is currently sixth in the championship, 19 points behind current leader Mark Webber.

In pre-season testing Kubica always felt the early signs were good, but just not as good as results have so far shown.

"We had some idea during the winter what the car was capable of," said Kubica.

"We understood its strengths and we worked on maximising them, but I'm still a bit surprised to have scored so many points which shows what a good job we are doing as a team.

"We have taken the opportunities that have come our way, especially in unusual races like Australia or the wet qualifying session in Malaysia.

"We've also taken our opportunities when the car has been strong, as we did in Monaco.

"So I think we can be very pleased with what we have achieved and proud of all the hard work at the factory to bring new parts for the car every weekend.

"But we know there is still a long way to go this season, and we need to continue pushing hard and improving the car."

The 24-year-old, though, is cautious as to what can be expected from him and Renault at this weekend's Turkish Grand Prix at Istanbul Park.

"Monaco was our strongest performance so far this season, but it's important the result doesn't make us over-optimistic because it will be difficult to repeat that pace this weekend," added Kubica.

"However, I still think we can be competitive in Turkey because the circuit characteristics are similar to Barcelona where we had good performance from the car.

"I'm also hoping the new updates we have for this race will help us close the gap and qualify a little bit higher up than we did in Barcelona."