Hamilton was trailing teammate Valtteri Bottas after the first run, but pulled out one of the laps of his career to steal pole position and the lap record at Monaco.
The Brit's run was less than a tenth faster than his teammate and after the week he's had, with Niki Lauda's death, Hamilton was understandably delighted and emotional as he got out of the car.
He told Sky Sports' Paul di Resta: "All the guys in the factory have put in everything. Valtteri has been quick all weekend. To get this, it means so much, I had to dig deeper than ever. The lap was beautiful, I feel amazing and super grateful.
"We have a great package and all drivers, whether their car is fast or slow, you take it to its limit, it's like wrestling a bull. The lap was hard, I had a moment at Rascasse but just managed to pull it off."