Piastri had led the opening stages after muscling his way beyond Kimi Antonelli at the start and looked set for victory after pitting for slick tyres midway through the race.

However, a lap later, Fernando Alonso crashed out to draw a Safety Car, handing Norris a lucky win.

Lewis Hamilton finished third after an early switch to dry tyres while officials were kept busy with a swathe of post-race investigations for Liam Lawson, Oliver Bearman, and Alex Albon.

UPDATE: Lawson stripped of Sprint points finish

That was on top of those dished out in race, which saw Max Verstappen handed 10 seconds for a clash in the pit lane, leaving him 17th in the classification having been fourth at the flag.

The formation lap began behind the Safety Car as race control attempted to clear some of the standing water from around the Miami International Autodrome.

Conditions had accounted for Charles Leclerc even before the race began when the Ferrari driver aquaplaned into the wall on his lap to the grid.

Also initially absent was Yuki Tsunoda, who lined up in the pit lane after Red Bull made changes to his car under parc ferme conditions.

Conditions had eased by the time the Safety Car led the filed away from the grid, the pack opting for intermediate tyres with the exception of Carlos Sainz, who’d opted for the wet tyres.

Behind the Safety Car, Verstappen ran off the road at Turn 17 after locking his brakes and skating off the road as the pack carried on for an additional formation lap.

As he didn’t drop to the rear of the pack, he was able to reclaim his position fourth in line.

Moments later, race control suspended the start procedure and showed the red flag.

It was a prudent move with Piastri reporting over the radio that visibility was the worst he’d ever experienced in a race car.

After a delay of around 20 minutes, the Safety Car led the pack out of the lane for the first of two laps.

That call was made in an attempt to give drivers an opportunity to assess the track and race control an opportunity to decide on a standing or rolling start.

Feedback was that the track had improved sufficiently for a standing start, Antonelli lining up on pole position some 33 minutes after initially planned.

When the race finally began, Piastri got the better jump and took the inside line at Turn 1 as Antonelli was elbowed down to fourth.

Norris claimed second with Verstappen third, while George Russell began challenging his teammate.

Antonelli complained he’d been pushed off at the race start as Piastri skipped out to a 1.7s advantage at the end of the first racing lap – official Lap 4 of the 19-lap Sprint.

Officials noted the clash, though it was quickly decided there was no further investigation necessary.

They also took an interest in Verstappen, who was flagged for starting out of position after he appeared to have pulled too far forward in his grid box.

Usually a slam-dunk penalty, the Dutchman was subsequently cleared with no further investigation.

It was a largely uneventful encounter for the opening 10 laps, with the front of the race quickly spreading out.

That saw Piastri head the field from Norris, Verstappen, Antonelli, Russell, Lewis Hamilton, Alex Albon, and Fernando Alonso.

Liam Lawson had made good early progress to sit just outside the points in ninth as he battled issues with his visor.

Conditions continually improved and, on Lap 11, DRS was enabled as radio chatter turned to whether the track was ready for slicks.

Well down the order, Tsunoda was the first to roll the dice as a dry line began to emerge with seven laps remaining.

Isack Hadjar boxed after 12 laps, the Racing Bulls driver sitting 10th at the time.

Hamilton also stopped and took on a set of soft tyres, as did Carlos Sainz and Lance Stroll.

On the drying track, Norris quickly closed up to his race-leading teammate as those on slicks began making significant inroads.

Tsunoda was rapid, prompting Red Bull to bring Verstappen into the pits.

As he exited the box, the Dutchman was released into Antonelli’s Mercedes.

The collision damaged Verstappen’s front wing while Antonelli was forced to continue straight back out on track without pitting.

McLaren had to react to the improving conditions and called Piastri into the lane with Norris carrying on, the last driver on track on the intermediate tyres.

He stopped next time around, boxing as the Safety Car was shown for Alonso, who’d crashed heavily.

The timing was perfect for Norris, as he followed the Safety Car down pit exit, allowing the Brit to take the lead over Piastri.

Hamilton’s early move onto slicks paid heavy dividends as he sat third with Verstappen fourth but set to take a 10-second post-race penalty. It was then Albon, Russell, Stroll, and Lawson.

The pit lane clash was also costly for Antonelli, slipping to 11th after having to complete another lap.

Officials also took interest in Lawson, after he tagged Alonso in the incident that prompted the Spaniard’s exit.

The race ended under Safety Car, with Norris heading Piastri and Hamilton to the line.

Verstappen was fourth at the flag but plummeted to 17th after his time penalty was applied.

That saw Albon fourth from Russell, Stroll, Lawson, and Oliver Bearman, though post-race investigations loomed over the latter two – Bearman for an unsafe release.