Lewis Hamilton is expecting a “harder fight” between Mercedes and their title rivals in the new season than was the case in 2014.

With the 12-day pre-season testing programme having now entered its second half, there appears to be growing evidence to suggest that the distant chasing pack of 2014 may have closed down part of world champions Mercedes’ large pace advantage from last season.

Hamilton’s team-mate Nico Rosberg has already said that the pace of Ferrari’s SF15-T in particular has “surprised” Mercedes. And while admitting himself that he had “zero” idea of where his team truly stood compared to the opposition, Hamilton also has the feeling that things will be closer this time around.

“I think we’ll have a bit of a better understanding next week [at the final test].” Hamilton said after signing off from the first Barcelona test with 101 laps and the third-fastest time.

“Everyone generally brings their upgrade for the first race. Then when you get to the first race it’s all different because the tyres start working better, the track is not so great at the beginning, but it gets better.

“It’s like driving blind, but that’s what I love about this sport – I don’t really know what’s to come.”

However, Hamilton then added: “I anticipate a harder fight this year.”

Although the form of Daniel Ricciardo at one stage of last season briefly looked as though it might propel Red Bull into the drivers’ title race, the harsh reality of 2014 was that Mercedes’ season-long advantage ensured Hamilton and Rosberg waged an exclusive duel for the crown.

But with 2015 testing approaching its final week, Hamilton sees a developing triple threat – although at the same time insists Mercedes haven’t simply stood still themselves.

“It looks like the Ferrari has potentially picked up their pace. Red Bull are just as quick, but just improved their engine maybe. And Williams are going to be there,” he said.

“But they’re all just focusing on themselves. I would imagine they’ve made a step, but so have we, and time will tell how big a step they have made compared to us.”

Admitting that it “feels like I could know more” about the W06 with only two days left in the car until the first race, the world champion, who had to pull out of Day One after 11 laps due to illness, added: “At the moment everything’s new and everything’s different. Even though it’s an evolution of last year’s car so much has changed and so it’s relearning your way again.

“I have a new engineer and he does things differently, but better in many respects. So it’s learning a new way to work with him and understanding the information given.”

One area where Hamilton is optimistic Mercedes have already managed to make progress is in the reliability of their car. Despite the utter dominance of the W05, the otherwise all-conquering machine let both drivers down on several notable occasions apiece during 2014 and the team have targeted an improved finishing record this term.

The evidence of the first seven days of testing suggests the W06 will be a more bullet-proof car.

“It’s too early to say but we’ve done so great mileage and there has been attention to the process and trying to improve on that area and I think the team have,” Hamilton said.

“The team manage it on percentage and ultimately you want to get 100 per cent reliability. Last year we were in the 80s and we want to be in the 90s. I do think it’s better but we still do have some things we’re trying to work on.”