Lando Norris suspects a power unit issue was the most likely cause for him being constrained to the McLaren garage in the closing stages of Friday's second practice in Monaco.
Norris clocked in fifth at the end of the session after a productive opening day in the Principality, just ahead of Mercedes' Lewis Hamilton and 0.444s down on the fastest time set by Red Bull's Max Verstappen.
"I think it was some PU issue we have had. I am not too sure what it is yet," he said when asked about the reason behind the premature end to his session.
"A decent day actually. It is nice to be back here, it is pretty awesome I'm not going to lie," he added.
"Tricky, a few wall touches and kisses but nothing worse than that.
"Positive, the pace looked pretty good actually, we made some good steps between FP1 and FP2 with the set-up and I am definitely getting a bit more confidence which is quite important around here."
McLaren endured a disappointing weekend last time out in Miami, with Norris and teammate Oscar Piastri running well adrift from the top ten in Florida.
While happy with his early form in Monaco, Norris wasn't surprised by his step forward in the pecking order which he believed was in part circuit specific.
"I wouldn't say it is too much of a surprise - not that we expected to be quick here but we just expected everyone to close up even more.
"It is the shortest circuit, the least straights which is a good thing for us in a way, but we have always been good here in the last few years.
"Just mechanically, the car works very well, we are good in the medium-to-high speed corners. The Swimming Pool section I have had good confidence and was able to go flat early on, which is a good thing.
"It is just trying to tweak the slow-speed corners which we are not bad in, it is just difficult. There is a very fine line in between overdoing it, underdoing it and that perfect sweet spot in the middle.
"When you can hook it up, it is just about there, it is just very difficult to replicate."
On the other side of the McLaren garage, Piastri who concluded his first day in an F1 in Monaco in P18, admitted that he had not yet come to grips with track's challenges.
"It was a bit of a tricky day, it’s such a challenging circuit and I’ve got a bit of work to do on my side, but that’s what happens when you’re getting up to speed," the Aussie explained.
"I think I’ve got the best out of each corner at least once, I’ve just got to put them all together on a lap now. We’ll keep working overnight and see what we can do.
"The car looks to be in a reasonable place, but the field is so tight again, so small improvements can have a big impact. We’ll keep pushing and look to unlock more pace tomorrow."
Keep up to date with all the F1 news via Facebook and Twitter
