The Belgian has lost out to Alonso in all five qualifying sessions, in part because he has had more technical issues and lost more track time.

He had a cleaner weekend in Spain, but after a solid Friday, he struggled for speed in qualifying.

He was left stranded in 19th in Q1 on a day when Alonso stunned the paddock by earning seventh.

"Today was a bit strange, I don't know exactly why," said Vandoorne. "Yesterday I was feeling very confident with the car, and very comfortable. I think we definitely made a step forward.

"I think tonight I will analyse with the team what didn't go 100 percent.

"Definitely we are more competitive, it just seems from my side I lost a bit of competitiveness compared to yesterday."

Vandoorne says there's no specific reason why he's found it hard to match his teammate.

"I don't really think it's a mystery. It's a combination of a few things, putting everything together at right time.

"Obviously the start of the season has been very tricky for my side, with quite a few problems.

"It's actually been the first weekend where I ran smoothly yesterday through practice one and practice two, where I felt very comfortable with the car, where we actually performed very well.

"But for some reason this morning was a bit more difficult, and we carried that through for qualifying.

"We just need to understand why, but I'm confident to get on top of the things, and once everything will fall together, then I'm sure we'll be able to progress."