McLaren star Oscar Piastri jumped the start before stalling the car at the Azerbaijan GP, and was given a penalty by the FIA. Piastri wasn't able to serve the penalty as he crashed out on Lap 1. However, the McLaren driver would not serve the penalty at the Singapore GP, and here's why.
Piastri crashed out in Q3 and started the race in P9, whereas his key title contender and teammate, Lando Norris, started in P7. The Australian jumped the start, realized his mistake, stopped the car, which led to him stalling, and was overtaken by everyone.
The championship leader, just a few corners into the race, braked late into the turn, had little to no grip, went wide, and slammed the car into the exit barrier, retiring from the race. The McLaren driver's jump start was noted by the race stewards, and Piastri was given a five-second penalty for the same.
But as Oscar Piastri had already retired the car, he couldn't serve the penalty. In such situations, according to F1 sporting regulations, if a car fails to serve the penalty due to retirement, the stewards can impose a grid drop for the following race, which in this case is the Singapore Grand Prix.

However, as per the penalty guidelines, Article 8 suggests that,
“In cases where there is a single 5s penalty which a driver is unable to serve due to retirement, the Stewards will not convert that into a grid penalty for a subsequent race. However, if there is more than one penalty, the Stewards may convert the 5s (and other) penalties into a grid penalty.”
As a result, Oscar Piastri escaped the grid drop for the Singapore GP. Fernando Alonso, who started right behind Piastri, also reacted to the Australian’s movement, jumped the start, and was awarded a 5-second penalty.
Oscar Piastri blames himself for the Azerbaijan GP woes
F1 championship leader Oscar Piastri had a weekend to forget at the Azerbaijan GP as the Australian crashed multiple times, gave away points to championship challenger Lando Norris, and made a rookie error at the race start.
Reflecting on the miserable weekend, including the jump start and the eventual crash, Piastri took full responsibility for the mistakes as he said,
“Certainly not my finest moment. I just anticipated the start too much, and it was a silly, simple error with that. Then, the crash – I just didn’t anticipate the dirty air in the way I should have. I clearly went into the corner way too hot and that was that,” said Piastri (via Sky Sports F1)
“The grip level was low, but I should have known that. I’m certainly not blaming it on anything other than myself, I just didn’t make the judgement calls that I needed to at the right time, and that’s obviously disappointing.”
Lando Norris finished P7 and cut Piastri's lead by another 6 points, with the gap down to 25 points.