After Michael Phelps’ record-extending performances in the pool largely dominated the narrative in the first week of the 2016 Olympics, another of the all-time great Olympians will start his attempts to steal the show this weekend. Already widely regarded as the best sprinter in history, Usain Bolt is aiming to complete an unprecedented “triple triple” in Rio.

Already Bolt is the first man in history to have won both the 100m and 200m in back-to-back Olympics, adding gold for Jamaica in the 4x100m on both occasions. At the age of 29, and eight years after he catapulted to superstardom in Beijing, he is seeking to contradict the accepted wisdom of how long a sprinter can remain in his prime.

It will be a busy next week for Bolt, culminating in the 4x100m relay final next Saturday. But the 100m comes first, with the opening round on Saturday. Both that opening round and the semifinals should be little more than fine tuning for the Jamaican, barring the type of false-start disaster that saw him disqualified from the final of the 2011 World Athletics Championships, the only time since 2008 that he has failed to win the event at a major competition.

In the final is where Bolt will come face-to-face with his biggest threat to becoming the first man ever to win three straight 100m golds. American Justin Gatlin has recorded the two fastest times in the world this year and is looking to win his second gold medal after crossing the line first in 2004.

At the time Gatlin won gold, he had already faced one doping ban, in 2001, although that was later lifted on an appeal over medication he had been taking for diagnosed attention deficit disorder. But in in 2006 he was given a four-year ban after testing positive for excessive testosterone levels.

Despite controversy following him wherever he has gone since, Gatlin returned to top-level sprinting and has run even quicker than before his suspension. But so far the top prizes have failed to follow his quick times.

Bronze medalist in 2012, Gatlin had recorded the five fastest times in the world going into last year’s World Championship. Yet when it came to the meeting with Bolt on the big stage, Gatlin wilted and his chief rival got the job done once again. Now aged 34, he likely has one last shot at another Olympic gold.

Yohan Blake, the second fastest man in history and silver medalist from 2012, will also hope to be hunting for a medal in the final. But the Jamaican has not competed at a major championship since the last Olympics after a string of injury problems, although he has got back to some kind of form this year, setting a time of 9.94 seconds.

Other threats for medals could come from Trayvon Bromell, who came second in the U.S. trials behind Gatlin in a time of 9.84 seconds. And then there is Frenchman Jimmy Vicaut, who earlier this year equaled the fastest time ever for a European when going 9.86 seconds.

The first round will get underway on Saturday, with the top two in each of the eight heats and the next eight fastest going onto the semifinals on Sunday evening. The top two in each of the three semifinals and the next two fastest will then go onto the final later that night.

Olympic Men’s 100m Schedule

First round heats: Saturday, 11 a.m.

Semifinals: Sunday, 8 p.m.

Final: Sunday, 9.25 p.m.