Red Bull's Max Verstappen believes that Mercedes still have a small advantage over Honda in terms of energy re-generation, which may have helped Mercedes to victory at Portimao last week.
Having been beaten by Lewis Hamilton in Portugal last time out, Verstappen was asked where he feels his RB16B was weaker than the Mercedes.
"We always evaluate, so you have to get the best out of it constantly," Verstappen told media, including RacingNews365.
"[There's] always strong/weak points, but is more about good balance, and that is not always easy. Also the Mercedes drivers drove with different wing settings, so always difficult to say.
"[I] still think [the] Mercedes engine is better, especially in terms of generating energy per lap but, in terms of pure power, we are better. Sometimes it is also how car is set up, and in Portimao [it was] not optimal for whatever reason."
With the balance of power swinging between Red Bull and Mercedes, apparently based on circuit characteristics, Verstappen explained that the team's level of understanding of the RB16B continues to improve and is eager to find out how that understanding translates to the Barcelona circuit.
"I think we understand the car a bit better," Verstappen said.
"The car keeps developing of course, so it's never easy to tune a car. It can depend on the track and its condition, but also different conditions, wind directions, these cars are very sensitive to that as well. It is never easy to be on top of that.
"We will see this weekend, but I am just happy that we are back on a track with normal grip and a track that we, all the teams, know very well. It will be interesting to see how competitive we are here."