The biggest nine and a bit seconds of the Rio Olympics will happen at 1.25pm today when Usain Bolt and his rival speed stars face off in the 100 metres.
For Bolt it's the start of a historic bid to become the first person to win the 100m, 200m and 4x100m relay at three successive Olympics.
Here's what you need to know as the fastest man on the planet prepares to hit the track.
WHEN DOES BOLT RACE?
Bolt was the fourth fastest qualifier through to the semi-finals of the 100m from the heats on Sunday.
He won his heat in a lazy 10.07, with his main rival Justin Gatlin the fastest overall with 10.01.
The world record holder (9.58s) will run in semi-final two at 12.07pm.
Barring injury or false start disaster Bolt will march on to the 100m final on at 1.25pm.
The 200m first round is on Wednesday at 2.50pm. The semi-final is 1pm on Thursday and the final is 1.30pm Thursday.
WHERE CAN I WATCH IT
You'll quite possibly be at work and will therefore need to negotiate with your boss to watch the biggest race in the Olympics. The good news? The 100m is going to be over in less than 10 seconds, and there's only so many ads the host broadcaster in Australia can squeeze into that time frame.
Radio Sport have live coverage while nzherald.co.nz will be live blogging the build-up and right through the semis and finals of both individual races.
WHO ARE THE DANGERS?
Bolt's No. 1 rival in the 100m will be American Justin Gatlin, who has the fastest time this year with 9.80. Gatlin went into last year's world championship as favourite to finally topple Bolt but was blown away by the Jamaican.
Bolt's main rival in the 200m is LaShawn Merritt of the USA. He has run a 19.74 this year and has three times under 19.80 in 2016. Bolt has declared he wants to break his world record of 19.19.
Bolt had a hamstring worry that kept him out of his national trials but it wasn't exactly tested in the heats.
"I'm happy to get the first one out, it felt OK," said Bolt. "It wasn't the best start. Hopefully tomorrow I can go much smoother, I'm feeling good, I'm happy.
"Now it's all about execution and getting it right when it comes to the final."