The opening round of the season had looked set to be a straightforward all-McLaren contest, with pole-getter Norris holding off parries from teammate Oscar Piastri, who started alongside him on the front row.
But the race turned on its head on lap 44 of 57 when heavy rain suddenly returned to Albert Park.
Both Norris and Piastri sailed off the road at the third-last corner as the grip instantly evaporated. Norris rejoined with his almost 20-second lead over the next non-McLaren greatly diminished, but Piastri wasn’t so lucky.
The local favourite, who had harboured hopes of being the first ever Australian to win their home grand prix, slithered back across the road and ended up stuck in the grass run-off zone. By the time he reversed out of the quagmire he was a defeated last.
Norris dived into pit lane for wet-weather tyres, but Verstappen, who had been a distant third before the rain, gambled on staying out, inheriting the lead. It briefly appeared to be a masterstroke, but two laps later he conceded that conditions had become too slippery, and he too pitted.
But the race was to come back to Verstappen on the next lap, when new teammate Liam Lawson spun into the barriers exiting turn 1. The safety car was called, and when all remaining drivers not yet on wet-weather rubber pitted, Norris and Verstappen rose to the top of the order.
The race resumed with five laps remaining, setting up an almighty duel between last year’s top two in the drivers championship.
The McLaren car should have been fast enough to comfortably hold off the Red Bull Racing machine, but the Briton was carrying damage from earlier in the race, and a wobble at the super-fast turn 6 right-hander allowed Verstappen to get within a second of the leading orange car.
The Dutchman, who had written himself off for victory ahead of the weekend, menaced in Norris’s mirrors, daring him to make another mistake. Through the middle sector, especially through the fastest turns, he had an advantage that seemed sure to give him a look at a race-winning overtake.
But Norris was steadfast in defence, nailing his lines through the crucial final sector to ensure Verstappen could never get a run at him down the front straight.
He took the chequered flag just 0.895 seconds ahead of Verstappen to put himself on top of the drivers championship for the first time in his career.
“To start the season off with a win is good enough, but to do it in such a stressful race, where it’s so easy to make a mistake, so easy to ruin everything so quickly… that’s what makes it rewarding and such a nice win,” he said.
“We worked a lot over the winter to prepare for a race like this because it’s where we threw away a lot of opportunities last season - Canada, Silverstone - where we were not the best at preparing and knowing how decisive we’ve got to be.
“Today we were very decisive… and that won us the race. Stressful but rewarding.”
Verstappen hadn’t expected his Red Bull Racing car to be in the mix for victory, having been surprised to have qualified third on Saturday night, and the reigning champion said his deficit in the first part of the race before the rain bunched up the field was more indicative of his team’s place in the order.
“If you look at the first stint, we were quite a bit off,” he said. “As soon as the tyres started to overheat we had no chance, McLaren just took off.
“We still have a lot of work to do to fight for a win, but I’m happy that we are second here. It’s basically one place better than we should have been.”
George Russell scored an unlikely podium for Mercedes, having never looked on the pace of either the McLaren or even the unconvincing Red Bull Racing car, which the Briton attributed to focusing on clean execution in tricky conditions.
“I think just staying out of trouble, to be honest, [was the key],” he said. “It was pretty clear from the beginning that these guys were too quick for us.
“I made a decision quite early on that the best way to approach this race was just to bring it home.
“Pleased to come home with this result, because I don’t think this is our strongest circuit.”
His teammate, Italian 18-year-old Andrea Kimi Antonelli, used the same clean-race strategy to great effect, rising from 16th on the grid to fourth. It was comfortably the best performance by a rookie, with four of the six fellow newcomers crashing out of the race and the fifth finishing last.
Thai star Alex Albon finished a superb fifth for Williams ahead of Aston Martin’s Lance Stroll and Sauber’s Nico Hülkenberg.
Charles Leclerc was Ferrari’s best-placed entry in eighth on a deeply dissatisfying day for the Scuderia borne of a lack of pace and some driver and strategic errors that left him down the order.
Oscar Piastri recovered to ninth with some gutsy overtakes, including one around the outside of Lewis Hamilton at the rapid turn 9-10 chicane, demoting the Briton to 10th in his first race for Ferrari.
Pierre Gasly, Yuki Tsunoda, Esteban Ocon and Oliver Bearman were the last of the finishers.
Rookie Isack Hadjar failed to take the start after spinning out on the formation lap. Jack Doohan’s second grand prix lasted just five corners before he lost control of his car and ended up in the barriers. Carlos Sainz found the wall just seconds later despite being behind the safety car.
Fernando Alonso crashed 32 laps into the race as light rain returned to the track, while Gabriel Bortoleto and Liam Lawson crashed out when it intensified with just over 10 aps to go.