Sebastian Vettel is still expecting a three-way fight for the win this weekend in Monaco, despite contrasting fortunes during practice on Thursday.

The German was half a second clear of Daniel Ricciardo's Red Bull in the second session, while Mercedes floundered in the lower half of the top 10, dealing with a set-up change that left them struggling with the tyres.

However, Vettel, who is yet to win in Monte Carlo and is driving for a Ferrari team that hasn't won there in 16 years, isn't getting carried away just yet. 

“I don’t know what happened [to Mercedes] today, it was a bit weird,” Sebastian commented. “But I'm pretty sure there was a reason, they will be back to full force on Saturday, so it will be close also with Red Bull around here.

“It’s important to have a good feel for the car to get the lap together so you cannot always go with the one time you set at the end of the day," he claimed, "but surely we managed to put it together, and we’re quite happy.

“I was very happy with the first run in the morning so since then we didn’t have to change that much but we improved the car for the afternoon. The conditions I think were also a bit like they will be on Saturday and Sunday.”

Despite the confidence, the four-time world champion admits there is some work needs to be done on improving race pace.

“I think we still do, and have to do, something to the car to be more competitive overall in the race,” he said. “But I think Kimi and myself we were both quite happy with the long run.”