Jenson Button may have a "good feeling about the first race" but he expects Mercedes could yet have the advantage over McLaren.
This week's Bahrain test has been dominated by the Mercedes-powered teams with Force India fastest on Day One, McLaren on Day Two and Lewis Hamilton in his Mercedes W05 setting the pace on Friday.
The British driver posted a 1:34.263 to beat Button by 0.713s.
And although it is widely thought that Mercedes-powered teams have the advantage, Button believes of those it is the full-works team that is ahead of the pack.
"I have a good feeling about the first race," Button told Sky Sports News.
"There's a lot of work to do for everyone before the first race and you can see by the difference in lap times from the quickest car and slowest car, it's massive.
"I'm sure we're not all running the same spec and the same tyres in the same conditions, but still there's a massive gap. I'm sure it will be closer by the first race and I feel that we will be ready for the first race. But there's a lot of work for us to do in the limited time we have."
Button had a busy day at the Sakhir circuit on Friday where he completed 103 laps including a full race distance during the afternoon's session.
It was a much better showing from the Brit and his McLaren team compared to last year with the troubled MP4-28.
Asked to compare the two cars, he said: "It's a great base, it really is. You can't really compare it to last year.
"The car goes in a straight line on the straights, it doesn't bounce up and down, you can see where you're going when you get to the corner - so it's a big difference!"
There is, however, still room for improvement with Button revealing that the MP4-29 could do with more downforce. That, though, he concedes is something every team wants.
"We're still lacking a lot of downforce, I think every team is, but compared to the car that was quicker than us today I think it's an area where we are weak at the moment.
"But the basic aim for us was to get a good car mechanically and a basic aerodynamic car and hopefully build on that through the season, but as much as we can for the first race.
"Yes, we're in a reasonable position. You'd like to be faster, I think every team except for the Mercedes team would be. When you look at other teams' test days and what they're up to you'd say that we're in reasonable shape."