Yuki Tsunoda after F1 Spain practice: "I don't have…

Yuki Tsunoda admitted to befuddlement over his lack of pace after Formula 1's opening practice sessions at the Spanish Grand Prix - revealing he "doesn't have any idea why I'm slow".

The Red Bull driver believed that, although his two Friday sessions were "smooth" and without any obvious issues, the ultimate pace was too slow and he was at a loss to explain why.

Tsunoda was heard to critique the RB21 via team radio, noting that he was suffering from sliding at both axles, and ended up six tenths slower than team-mate Max Verstappen amid the soft-tyre qualifying simulations.

Like Verstappen, he did long runs on both medium and soft tyres - but was visibly off the four-time champion's pace across the laps. GPS data suggests a significant shortfall in carrying speed through Turn 9 and Turn 10 versus Verstappen.

"It was tricky," was Tsunoda's view of the sessions. "To be honest, in terms of the first day compared to any other grand prix, it felt pretty smooth.

"I think I made progress from FP1, FP2. But to be honest, I just don't have any idea why I am slow. The lap was pretty good as well, considering FP2 and obviously it's not like fully 100%.

"But obviously it's not the gap that I'm expecting. So it's hard to even tell what kind of exact limitation I have in terms of balance, it's OK. We have to see what we can improve, but currently [I'm] struggling.

Yuki Tsunoda, Red Bull Racing (Photo by: Red Bull Content Pool)

"Hopefully we can find something, otherwise, it's really tough. It's not like I had a massive mistake and I'm behind and being compared to competitors; if I had a mistake and without results, I'm happy, actually, but it's not like that.

"It will be a longer night than usual, probably, but obviously there's a curfew and everything. I'll try my best to find a solution. Currently, it's not very clear."

From Verstappen's point of view, the Dutchman enjoyed an "OK" Friday and noted that there was a tentative feeling of greater positivity versus some of Red Bull's FP1-FP2 run-ins to the weekend so far this year.

He noted that he still wanted more out of the car to feel truly comfortable, as he was at Imola, but was ultimately pleased not to feel "out of it" after the opening sessions.

"The track is always very enjoyable to drive. It's quite hot out there as well, especially for the tyres. But I think it was an OK Friday," Verstappen explained.

"We've had worse Fridays, but I felt a bit happier with the car. We're still not, I think, where we want to be, but it was definitely a bit more positive.

"Every track is a bit different, but the feeling, I still want a better feeling from the car. I've also had Fridays where we were completely out of it. So, it's a bit more, I would say, in the middle."