Pascal Wehrlein does not think Manor is close to its full potential yet despite a solid start to life with Mercedes engines.
On Tuesday Wehrlein finished eighth overall and brought the lap count on the MR05 up to 125 for two days of testing in Barcelona. The team has been boosted with a Mercedes engine deal and a technical partnership with Williams, as well as a raft of personnel changes.
Wehrlein, himself one of those changes after being signed for his rookie season, thinks there is much more to come from Manor.
"I am really happy with today," the German driver said. "I think we improved the car quite a lot from yesterday to today. For sure we can still improve the car and we need to work on it, but for my first two days I am impressed and really happy.
"There is more potential after the two days. I hope we have not shown our full potential, there is definitely more to come -- but you never know."
Wehrlein says there has been a clear step forward made over the two days but does not think this is surprising given where Manor came from, having competed last season with a year-old Ferrari engine and what was effectively a 2014-spec car.
"Last year they had an old car, an old chassis, and they didn't develop much. The balance of the car has improved and the Mercedes engine is definitely better than the 2014 engine they had last year. Many things, we have many new people in the team. I hope that also I'm a reason why it's getting quicker.
"The balance yesterday wasn't great to start with, which is normal with a new car and new engine and everything was new. We improved so much during the day yesterday and today and in the morning I felt much better in the car, but that's normal with a new car, you have to adapt and adapt to set-up. Manor has made a big step, the last car they have driven was the 2014 car so it's a big change for everyone."