However, it was far from straight-forward for Sainz whose race could have been over after lap one, but a red flag and a race re-start offered him a lifeline.
Behind the them, the Red Bull of Sergio Perez was involved in a terrifying collision with both Haas drivers, destroying their cars and ending their weekend early.
The second race start was less than eventful with all drivers' getting away cleanly, and a procession around the principality ensued.
Here is what the top three had to say following the Monaco Grand Prix...
Charles Leclerc
"No words can explain that. It's such a difficult race, I think the fact twice I've been starting on pole position and we couldn't quite make it makes it even better in a way.
"It means a lot, obviously. It's the race which made me dream of becoming a Formula 1 driver one day.
"Fifteen laps to the end you're hoping nothing happens and the emotions are coming.
"My dad has given everything for me to be here and it was a dream of ours for me to race here and win here, so it's unbelievable."
Oscar Piastri
"Tricky race. The pace at the beginning was incredibly slow. I had one little half look before the tunnel but didn't have a small enough car to fit into the gap!
"Thanks to the team. It's been a great weekend all-round. Nice to put a result on the board. I've been strong the last few weekends but didn't have the result to show for it. Nice to have a podium.
"Charles has been mega all weekend. They have been quick from the very first lap.
"I'm happy with P2. A good result for the team. Very, very happy."
Carlos Sainz
"It was a tight one and a very bad feeling in lap one which very quickly turned into a really good feeling after getting reinstated in P3.
"From thereon really, the race pace was good as we expect, it's just impossible to get past on the streets of Monaco.
"But I'm incredibly happy to see Charles win on his home Grand Prix.
"To be able to share this podium with him in P3 is great for the whole team, and it feels like we're getting stronger and stronger."