Charles Leclerc triggered frenzied Ferrari celebrations on Sunday after holding off a race-long Mercedes challenge to take the Italian F1 team's first home Grand Prix victory since 2010.

The 21-year-old Monegasque racer, who won his maiden GP in Belgium last weekend, was exultant as a vast army of Ferrari fans in an estimated crowd of more than 150,000 celebrated deliriously.

Valtteri Bottas was second for Mercedes with five-time world champion Lewis Hamilton a distant third after tire wear took its toll in a thrilling battle with the 21-year-old Monegasque.

"I think if you have to win one GP with Ferrari, it's the Italian Grand Prix," said an exhausted Leclerc after winning the 90th edition of the GP for the Italian team in their 90th year. "I came here with my first win and to win my second one here straight away with all the fans is just unbelievable."

"I don't have the words to describe this. I have never imagined it, I've never dreamed of something like this - it is above everything I have imagined in my career and in my racing life to have a podium like this," he said. 

A sea of fans, who starved of success at Monza since Fernando Alonso won in the red overalls, swept onto the pit straight to party below the overhanging podium with flags and flares.

"Winning here is just a dream," continued the winner, switching to fluent Italian to address a crowd cheering a fitting triumph on the 90th anniversary of both Monza and F1's most glamorous team.

"Last weekend (in Belgium) was my first victory, but the emotion of winning here is 10 times that," said Leclerc, now a two-time winner – and Ferrari's sole one so far this season – in only his 14th race for Ferrari.

Hamilton's lead over closest rival Bottas was cut to 63 points from 65, with the Briton limiting the damage by making a late pit-stop for fresh tires to set the fastest lap and gain an extra point.

"He did a great job, congratulations to Ferrari," said Hamilton, who took the fight to Leclerc from the start but dropped behind Bottas 10 laps from the end when he cut the first chicane. "A lot of pressure from both Valtteri and I. I did the best I could. Obviously following so closely for such a long time, the tires eventually just went off the cliff."

"But nevertheless they were just quicker today, quicker in a straight line, so even if we did get close we couldn't pass. So not our day but still strong points for the team," added the 34-year-old.

(With input from AFP and Reuters)