Max Verstappen tip-toed through the rainswept conditions in the latter stages of his victory in Sunday's Monaco Grand Prix and then declared he had been lucky to survive several brushes with the barriers.

In the aftermath of a challenging race in increasingly difficult conditions, Red Bull's defending world champion and the current series leader admitted he was fortunate in the way his car smacked the railings.

"I clipped the walls a few times," he said after his second win in the Mediterranean principality and fourth this season.

"It was super difficult out there today, but that's it. That's Monaco."

He explained that he was struggling while racing on a set of worn medium tyres, having started the race on them, as the rain began.

"I locked up the rears and I couldn't get out of it as the car slides," he said.

"So it was about trying to control that with a bit of drifting. And, luckily, the wall stopped that in a way from sliding anymore."

He added that the way in which he glided into the walls in the closing stages of the race had probably saved him from a more damaging contact.

His comprehensive triumph, after a virtuoso lap had secured his first Monaco pole on Saturday, brought him his 39th career victory and a 39-point lead over team-mate Sergio Perez in the drivers' championship ahead of next weekend's Spanish Grand Prix, the scene of his maiden win for the team.

Victory also gave some relief to agitated team boss Christian Horner who admitted he had felt apprehensive ahead of the Monaco race.

"We were on the ropes here," he said. "We knew coming into this weekend that it was going to be our biggest challenge in the first half of the year and the low-speed nature was playing to their strengths.

"We actually thought Ferrari might be the main opponent, but Fernando's just been on fire all weekend. I mean, unbelievable.

"When they pulled the covers off, you could see quite a few of them went on the hard tyre and with rain around.

"In the race, it felt like maybe we had gone a lap too long before going on to the intermediates. Had Fernando picked the inters, it would have been much tighter and put more pressure on our pitstop.

"When you're the lead car, you can only lose. You've got nothing to gain. And you've just got to try and work with the conditions, but thankfully, he picked the slick tyre just as the rain came in stronger."