Voting has opened for the BBC's World Sport Star of the Year 2021 award.

Voting will stay open until 13:00 GMT on Tuesday, 14 December and the award will be presented during the BBC Sports Personality of the Year show live on BBC One on Sunday, 19 December.

Who are the World Sport Star contenders?

Victory over Caleb Plant in November made Alvarez the first undisputed super-middleweight champion of all time.

The Mexican boasts a record of 57 career wins, two draws and just the one loss - to Floyd Mayweather in 2013.

Alvarez has his sights on going further as he seeks to cement his legacy, with plans to move up to cruiserweight to fight Ilunga Makabu for the WBC title in a bid to become a five-weight world champion.

Irish jockey Blackmore became the first female rider to win the Grand National at Aintree with victory on Minella Times.

No other woman had ever finished in the first four of the famous race, which takes place over more than four miles and 30 fences.

Blackmore also became the first woman to be leading jockey at the Cheltenham Festival in March, where she racked up six victories.

The American football legend extended his record for Super Bowl wins to seven as he helped the Tampa Bay Buccaneers to a comfortable victory over the Kansas City Chiefs in February.

Brady also became the NFL's leading passer in October when the Bucs won at his former side the New England Patriots.

The quarterback got the 68 yards he needed to pass the 80,358-yard milestone set by Drew Brees.

The Serb came close to becoming the first man in more than 50 years to win all four tennis majors in the same year.

Djokovic sealed victories at the Australian Open, French Open and Wimbledon to draw level with Rafael Nadal and Roger Federer on 20 major titles.

He made it to the US Open final to bring the four-timer within his grasp, before going down in straight sets to Daniil Medvedev.

Thompson-Herah made history as the first woman to complete the Olympic sprint 'double double'.

The Jamaican became the second-fastest ever woman in both events, behind only Florence Griffith-Joyner, as she took gold in the 100m and 200m.

Thompson-Herah successfully defended her Rio titles despite being hampered by an Achilles tendon injury for several seasons.

Verstappen featured in a thrilling duel for the Formula 1 world title with British driver Lewis Hamilton.

Seeking his first World Championship, the Red Bull driver was level on points with his Mercedes rival, the seven-time champion, with one race to go.

The Dutchman's victories included one at his home grand prix in September, where he was cheered on by 65,000 enthusiastic fans.