Lewis Hamilton, Sebastian Vettel, Valtteri Bottas, Kimi Raikkonen, Formula One news, 2017 Formula One season
Sebastian Vettel during a testing session.Reuters.

The penultimate day of Formula One testing saw Ferrari's Sebastian Vettel top the time sheets as he went 0.328 seconds faster than Mercedes' Lewis Hamilton. This marks the third time that Ferrari have topped the time sheets during preseason testing, following two for Kimi Raikkonen in the opening week. Hamilton has topped one and Mercedes teammate Valtteri Bottas two.

Also read: Lewis Hamilton compares his new car to a boat

Mercedes will be looking to retain their constructors' championship in the upcoming Formula One season, but Hamilton feels that they could face a lot of competition from Ferrari this season. The Brit has been really impressed with Ferrari's performance in testing so far and said at the start of this week's test that the Italian team is emerging as favourites for the new campaign.

A lot of people noticed that Vettel seemed to slow down as he approached the finish line and Hamilton too paid close attention to that and said that Ferrari are bluffing about their true pace ahead of the start of the season.

"I think Ferrari are bluffing and that they are a lot quicker than they are showing. They're very close to us. It's difficult right now to say exactly who is quicker. But they are very close, if not faster. Whatever the case, I can't wait to go out and compete" ESPN quoted Hamilton as saying.

Hamilton's teammate Bottas, who replaced the reigning world champion Nico Rosberg, has been quite impressive in testing so far, as he topped the time sheets on two occasions, but in the latest session the Finnish driver only managed the eighth best time. The former Williams man said he was aware of Ferrari's pace and thinks Red Bull is also a danger for Mercedes.

Mercedes have dominated F1 since the turbo-hybrid engine formula was introduced in 2014, but Bottas says the Mercedes team is not as confident as they were in previous seasons after looking at the performance of the other cars in testing.

"I think that is very difficult to say. We are definitely not confident that we are in the front. We are not relaxing or being in a comfortable situation at all. I think we do feel the other teams have made good progress over the winter. I think Ferrari is looking very strong, Red Bull can always surprise" Bottas said.

"Even some other teams can be close but definitely some other teams like Ferrari, they are looking very solid and strong and fast. Who knows what people are bringing to Melbourne. We are aware that we should not underestimate them. We're not at this point saying 'OK, we are the number one', we are just working flat-out."