The 2021 Australian Open was a Grand Slam tennis tournament that took place at Melbourne Park, on 8–21 February 2021.

In the final, Naomi Osaka claimed her fourth Grand Slam singles title, defeating first-time Major finalist Jennifer Brady in straight sets.

There are singles and doubles events for both boys and girls (players under 18), which are part of the Grade A category of tournaments.

[4] There are also singles, doubles and quad events for men's and women's wheelchair tennis players as part of the NEC tour under the Grand Slam category.

For the first time in Grand Slam history, Hawk-Eye Live electronic line judging was used for all matches.

[5] On 17 December 2020, due to mandatory 14-day quarantine on all arrivals into the country Tennis Australia announced that the start of Australian Open would be delayed by three weeks from 18 January 2021 to 8 February.

[6][7] To honour key workers, recordings of their voices were broadcast for line calls as part of the electronic system.

[5] On 4 February 2021, all of the scheduled day's events leading up to the tournament, including the ATP Cup and warm-ups, had to be suspended after a 26-year-old man working at the hotel players were quarantining at tested positive for COVID-19.

Victorian premier Daniel Andrews stated that the 8 February start would not be affected due to the schedule change.

[12] On 12 February 2021, a five-day snap lockdown and stay-at-home order was declared by the Victoria State Government beginning at 11:59 p.m. AEDT, due to a cluster of active cases linked to another quarantine hotel in Melbourne, presumed to involve a highly-infectious variant of SARS-CoV2.

As a result, the tournament was played behind closed doors from 11:30 p.m. AEDT that night;[13][14] the final match of the day between Novak Djokovic and Taylor Fritz was suspended at that time to escort spectators from the premises.

4 Daniil Medvedev in straight sets to win his 18th Grand Slam singles championship and his ninth overall (and third consecutive) Australian Open, in a game that lasted an hour and 53 minutes.

[19] 2001 Wimbledon winner Goran Ivanišević, who was part of Djokovic's coaching staff, praised his play and total control through the game, calling his performance, "a masterpiece".

[20][21] Osaka progressed through the tournament having lost only one set, and became the first woman to win each of her first four Grand Slam singles finals appearances since 1991.

Each player held service once to tie at 4–4 before Osaka took the lead at 5–4 and broke Brady's serve to win the first set, 6–4.

Osaka took advantage of two forced errors and won the game without conceding, ending the set at 6–3 and winning her the title after 1 hour and 17 minutes.

[26] Following the conclusion of the match, Sabalenka announced that the pair would not play doubles together for the remainder of the year, so that she could focus on singles.

[28][29] The final of the wheelchair men's singles took place on February 17 between two of the unseeded players after the top two seeds fell in the quarter-finals and semi-finals respectively.

[31] The final of the Quad Singles was played on the 17 February between Australian top seed Dylan Alcott and Dutch player, Sam Schröder.

[34] The wheelchair women's doubles final, which was played on 16 February, was won by Dutch duo Diede de Groot and Aniek van Koot in straight sets.

[34] The wheelchair quad doubles championship match, a rematch of the last four finals (most recently in 2020), was held on 16 February with Dylan Alcott and Heath Davidson defeating Andy Lapthorne and David Wagner in a third-set tiebreak.