Horner expects Red Bull to struggle in Canada, Azerbaijan, Austria

Red Bull Formula 1 chief Christian Horner expects the next three races in Canada, Azerbaijan and Austria to be difficult for the team given its current power weakness.

Red Bull has largely found itself to be the third-fastest team at races so far this season, with the deficit of the Renault power unit holding back the RB13 chassis in the fight against front-runners Mercedes and Ferrari.

Progress was made with an update for the start of the European season that saw Red Bull jump ahead of Mercedes last weekend in Monaco as Daniel Ricciardo picked up a podium finish.

Speaking after the race, Horner said Red Bull was becoming increasingly comfortable and understanding of its RB13 car, but added that he is anticipating a run of tough races in the next six weeks.

"I think we are understanding the car better and developing the car better with better performance out of the car. That has worked to good effect on this circuit," Horner said.

"I am a little worried for two weeks and four weeks time in Canada and Baku because there are completely different challenges. The next three circuits are actually really tough for us. Canada, Baku and Austria they are going to be our biggest challenges on the calendar bar Monza.

"If we can perform OK at those next three venues, then what is in the pipeline coming further in the season I think the second half of the season can be stronger than the first half."

Renault is planning to give Red Bull an engine update in the next couple of races, but Horner did not want to be drawn into a discussion about when it would arrive.

"I think you'll have to speak to Cyril [Abiteboul, Renault F1 chief] about that because it get into hot water every time I mention the word," Horner said.

"I don't want to talk about engines anymore, just about TAG Heuers."