Victory for Max Verstappen and a fourth-place finish for Sergio Perez handed Red Bull the lead in both world championships for the first time in the hybrid era as Mercedes endured a disastrous day.

Valtteri Bottas retired from second place due to a botched pit stop, while a poor strategy call meant Lewis Hamilton could only finish where he started in seventh.

Mercedes’ collapse, coupled with Verstappen’s maiden Monaco win, saw the Dutchman enjoy an 18-point swing in his favour to move into the lead of the championship for the first time in his F1 career.

“It was important to take our chances here,” said Horner.

“Mercedes had a rare off-day and it was important to convert that. So as a team, we’ve done that.

“We leave here leading both championships for the first time in the hybrid era, so that’s really encouraging.

“Nobody is getting carried away, there’s still an awfully long way to go in this championship [but] to be as close as we are at this stage is very encouraging.”

While Horner acknowledged that Verstappen benefitted from polesitter Charles Leclerc being unable to participate in his home race following a driveshaft hub failure on his lap to the grid, the Red Bull boss felt it was a thoroughly deserved win nonetheless.

“You’ve got to feel for them a bit,” Horner said of Ferrari. “They made a calculated risk and it didn’t pay off.

“Max was disappointed [after qualifying]. We didn’t get to see what that lap could have delivered but he dealt with his frustration well and when the opportunity presented itself he took it with both hands.

“Max really took control of the race from the start and literally controlled the whole afternoon,” Horner added.

“He was quick when he needed to be, he was looking after his tyres very well. A phenomenal performance.”