Welcome to ESPN's fan vote, where you, the reader and sports fan, will decide which individual or team has been the most dominant in the 21st century.
In our second quarter-final, we have arguably the greatest tennis player of all time squaring up against the most dominant sprinter of all time.
(Please vote in the poll at the bottom of this page to decide the winner.)
Roger Federer at Wimbledon (2003-2007)
Roger Federer's breakthrough at a major came when he won his first Grand Slam title at Wimbledon in 2003 at the age of 21. The win was followed by his rapid rise, soon after which he was ranked World No. 1 for the first time ever in February 2004. Such was his dominance that he ended up holding the position for 237 weeks in succession.
During that time, it was his invincibility on grass that stood out, as he won a staggering 65 straight matches on the surface. His silky forehands and effortless volleys enabled him to win every edition of Wimbledon from 2003 to 2007 -- becoming only the second man after Bjorn Borg to win five successive titles at the Championships in the Open era.
Usain Bolt at the Olympics (2008-2016)
Usain Bolt -- the world's fastest man, a record he has held for 13 years now -- is the most dominant sprinter of all time.
Here are the facts: He won the 100m and 200m across three consecutive Olympics, the only person in history to achieve this feat. Include the relays, and he has eight Olympic golds. Between 2009- 2015, he won the 100m, 200m, and 4x100m relay in every World Championships (except for a false start disqualification in 2011). His 11 World Championship golds are more than anyone in history.
In this period, he went on a run (no pun intended) where he won 17 straight 200m finals, and 14 straight 100m ones. He broke the 100m record thrice, the 200m record twice and the 4x100m relay record thrice.
And he made it all look as easy as a jog in the park.
(If the poll doesn't load, click here to try again. The poll will close at 4PM IST on Tuesday, July 7)