Valtteri Bottas says Williams can thank Mercedes for a productive second test in Bahrain as the latter seems to their engine working well.
While the Renault runners once again struggled to put in the laps at the Sakhir circuit last week, the same cannot be said of those powered by Mercedes.
Not only were the Mercedes teams quickest on all four days but they were also the most productive.
Williams, who swapped from Renault to Mercedes in time for this year's Championship, covered the most laps at 323 while the Mercedes works team was second in line.
"If we have more of these kinds of days and if some other teams continue struggling then for sure we have an advantage, and I think a big thanks to this is the Mercedes," Bottas told Autosport.
"The work with them has been very good so far; the engine side is working well. We did the amount of laps of two races without any problems, which is very important."
The Finnish driver, who will team up with new Williams signing Felipe Massa this season, admits the situation is looking better for his team than it did at this stage last year.
"At this point compared to last year is it's looking better for us, and that's definitely our goal to make a good step from last year, because it was not where we should be.
"But we're not getting too excited yet. We've no clue what the others have been doing. Looking at the lap times it's still very difficult to know, so let's wait a bit and see.
"I think Ferrari is also looking strong [with a] strong engine. [Their] reliability is also not too bad, and we'll see how much Renault can improve.
"I think we should not underestimate anyone, but we are hoping we will be in this top 10 group and my feeling, at least at the beginning of the season, is that it could be Mercedes-powered cars [at the front] but let's see.
"I think the field could actually be quite tight - especially the top 15."