Helmut Marko says that Red Bull's RB18 has the potential to be even faster, despite having won four races in a row.

Marko admits that the car is still overweight, even though Red Bull is trying hard to reduce it at the beginning of the season.

He predicts that Red Bull could gain "a few tenths of a second" if it can shed the extra weight, a daunting prospect for Ferrari, which is already having trouble keeping up.

Marko believes Ferrari is already close to Formula One's minimum weight limit, but he thinks Mercedes, which had good pace at the Spanish GP, also still has weight to lose.

"Weight loss doesn't happen overnight," Marko told , with the team having faced problems with DRS for trying to reduce the weight of their car too quickly.

"So it's a positive that we still have a reserve of a few tenths of a second once we get to the minimum weight."

"We are still too heavy. However, we believe that Ferrari is already close to the weight limit, while Mercedes has about the same weight as us."

Despite Sergio Perez's victory, Ferrari seemed to have the fastest car in Monaco, where Charles Leclerc led all free practice and qualifying.

However, Marko says that the weekend in Monte Carlo did not show the real picture, with Red Bull being much closer to Ferrari than most think.

"The practice results in Monte Carlo say nothing about the real balance of power between Red Bull and Ferrari. Max (Verstappen) had problems in one corner in all four sessions (including qualifying) that cost him three tenths of a second."

"In sectors two and three, Verstappen was less than a hundredth or even ahead of the rest. On his last lap (in qualifying), he finally got the first sector right, and according to our prediction, he would have been on the front row at least."

"I think Leclerc could not be reached, but that means that those three or four tenths behind did not show the real scenario."