Lewis Hamilton is worried Red Bull will benefit from a new "bendy" rear wing, giving them a straight-line speed edge at the Spanish Grand Prix.

The Mercedes driver made history in qualifying on Saturday, notching up his 100th Formula 1 pole after narrowly beating Max Verstappen by just 0.036s in Q3 at the Circuit de Barcelona-Catalunya.

And speaking after the session, Hamilton admitted the pursuit of that milestone figure hadn't been easy as he was still changing his W12 entering Q1.

“I had a bit of anxiety about the changes we were potentially going to make for qualifying,” he said.

Also Read:

• Hamilton credits 'immense' Mercedes journey after 100th F1 pole
• Hamilton & Verstappen expect clean racing but might be 'sick of each other' by Abu Dhabi

“We’re always trying to make the car better, but it’s a bit of a gamble because you’ve got to also keep the race in mind.

"Anyway, we made this change and as soon as I got out I was like: ‘This is the wrong one!’ It was my call at the end, but it was really hard. The set-up that I made I just had so much understeer.

“The car was so lazy, it wouldn’t turn into the corner the way I want, so you’re waiting and waiting and waiting.

"It’s why I was behind the whole way through qualifying," he claimed. “I was making small adjustments within what we’re able to change in order to get the car to turn.

"That’s a combination of many things, and then it’s just pulling every millisecond together.”

In the end, Hamilton credited his "best lap" of qualifying for securing that 100th F1 pole.

However, in Barcelona, that isn't always the best place to be at the start of the race...

“It’s the goal to get on the front row and be first,” Lewis told Sky Sports. “But it’s 600 metres down to Turn 1, there’s often a headwind and it means the guys get to drag you, which is really difficult.

“The Red Bulls are really fast on the straights. They have this bendy wing on the back of their car which they put on today and they gained at least three tenths from this wing.

“So they will be quicker down the straights than us and it will be hard to keep them behind, but that doesn’t mean it will be impossible. Timing and rhythm will be everything tomorrow.”

As for Red Bull's perspective, Verstappen wasn't displeased with second on the grid.

"We know that they're hard to beat around here but to be that close I can be happy with that," said the Dutchman.

"It was good. Struggled a little in Q1 but I think then we sorted out the balance for Q2 which was pretty good. And then Q3, for me to be honest, both laps were pretty decent.

"The second run was a little bit worse for whatever reason. It's quite gusty right here so the wind changes a lot, but nevertheless, I think second for us on this track was very good today."

And as for the possibility of trying to out-drag Hamilton at the start on Sunday...

"Yes, it's a long run into Turn 1," Max agreed. "But of course first you have to make sure to have a good start!"