Massa and Stroll's last lap F1 Italian GP battle 'scary' - Williams

Stroll, who started the Monza race from second, was running seventh when he picked up a flat spot, which allowed Massa and Sergio Perez to put pressure on him on the final lap.

The two Williams drivers touched as Massa attacked his team-mate while simultaneously trying to defend from Perez, but the three ultimately all held position.

"We absolutely let them race and that was probably more to make sure Perez didn't overtake Massa rather than put the pressure on Lance," Williams told Autosport.

"It was a little bit scary the last lap, but we have total trust in Felipe.

"He's an old hand, an experienced driver and he knows about taking team-mates off and the rules around that.

"We had some issues with both cars at the end with some overheating, so I'm glad to get them finishing seventh and eighth."

Massa, who scored points for the eighth time in 13 races this season, felt he was fair when battling his team-mate.

"I had some fight with my team-mate," said the Brazilian. "I braked on the left on the main straight.

"He just moved a little bit too much on my side and we touched wheels, but nothing happened which was good.

"It was a good race for both cars, points are always important."

Stroll's seventh place marked his fourth points finish of the year, helping him reduce the gap to his team-mate in the drivers' standings to seven points.

It followed an impressive qualifying performance, where he was quick through all three segments of a wet session to end up fourth fastest and second on the grid after penalties for the two Red Bulls.

"With Lance qualifying where he did, it's testament to the performance he has," said Williams.

"When he drove the car for the first time in the wet [in qualifying] and did what he did - it was fantastic.

"To have the car to come home where it did, it's a happy way to end the weekend."