# 1921 Australasian Championships – Singles

Rice Gemmell defeated Alfred Hedeman 7–5, 6–1, 6–4 in the final to win the men's singles tennis title at the 1921 Australasian Championships.

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* r = Retired
| Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Finals | Finals | Finals | Finals | Finals |
| Rice Gemmell | Rice Gemmell | 6 | 6 | 6 | | | | | | | | | | | | |
| E. M. Barker | E. M. Barker | 0 | 3 | 0 | | Rice Gemmell | Rice Gemmell | 6 | 6 | 6 | | | | | | |
| Clarence Treloar | Clarence Treloar | 6 | 6 | 6 | | Clarence Treloar | Clarence Treloar | 2 | 1 | 3 | | | | | | |
| W. Henville | W. Henville | 3 | 2 | 2 | | | | | | | | Rice Gemmell | Rice Gemmell | 7 | 6 | 6 |
| Alfred Hedeman | Alfred Hedeman | 6 | 6 | 6 | | | | | | | | Alfred Hedeman | Alfred Hedeman | 5 | 1 | 4 |
| Norman Kenneth Brearley | Norman Kenneth Brearley | 2 | 1 | 3 | | Alfred Hedeman | Alfred Hedeman | 6 | 3 | 6 | 6 | | | | | |
| Keith McDougall | Keith McDougall | 2 | 12 | 6 | 6 | Keith A. McDougall | Keith A. McDougall | 4 | 6 | 1 | 2 | | | | | |
| W. Hayman | W. Hayman | 6 | 10 | 2 | 0 | | | | | | | | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| | | | | | R. T. H. Gemmell | 6 | 6 | 4 | 6 | | | | | | | | |
| | | | | | D. Cameron | 3 | 1 | 6 | 0 | | | | | | | | |
| | | | | | | | | | | R. T. H. Gemmell | 6 | 6 | 6 | | | | |
| | | | | | | | | | | E. M. Barker | 0 | 3 | 0 | | | | |
| | | | | | E. M. Barker | 4 | 6 | 6 | 6 | | | | | | | | |
| | | | | | Holliday | 6 | 2 | 4 | 2 | | | | | | | | |
| | | | | | | | | | | | | | | R. T. H. Gemmell | 6 | 6 | 6 |
| C. L. Treloar | 6 | 3 | 6 | 6 | | | | | | | | | | C. L. Treloar | 2 | 1 | 3 |
| William McLeod Cleland | 4 | 6 | 1 | 4 | C. L. Treloar | 7 | 6 | 6 | | | | | | | | | |
| Leonard McDaniell | 6 | 6 | 6 | | Leonard McDaniell | 5 | 2 | 4 | | | | | | | | | |
| Malcolm Plaistowe | 2 | 4 | 0 | | | | | | | C. L. Treloar | 6 | 6 | 6 | | | | |
| W. Henville | 3 | 2 | 8 | rtd. | | | | | | W. Henville | 3 | 2 | 2 | | | | |
| P. Mills | 6 | 6 | 6 | | W. Henville | 6 | 6 | 7 | | | | | | | | | |
| S. Davis | w/o | | | | S.Davis | 1 | 3 | 5 | | | | | | | | | |
| Edward W. Stokes | | | | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| | | | | A. H. Hedeman | 6 | 4 | 6 | 6 | | | | | | | | | | | |
| | | | | Forsaith | 4 | 6 | 1 | 3 | | | | | | | | | | | |
| | | | | | | | | | | A. H. Hedeman | 6 | 6 | 6 | | | | | | |
| N. Brearley | 6 | 6 | 6 | | | | | | | Norman Kenneth Brearley | 2 | 1 | 3 | | | | | | |
| Sturm | 4 | 3 | 1 | N. Brearley | 3 | 3 | 11 | 6 | 6 | | | | | | | | | | |
| Linwood | 6 | 6 | 6 | Linwood | 6 | 6 | 9 | 2 | 4 | | | | | | | | | | |
| Fairbridge | 2 | 0 | 0 | | | | | | | | | | | | A. H. Hedeman | 6 | 3 | 6 | 6 |
| | | | | | | | | | | | | | | | K. A. McDougall | 4 | 6 | 1 | 2 |
| | | | | W. Hayman | 2 | 6 | 7 | 5 | 6 | | | | | | | | | | |
| | | | | McGibbon | 6 | 2 | 5 | 7 | 2 | | | | | | | | | | |
| | | | | | | | | | | K. A. McDougall | 2 | 12 | 6 | 6 | | | | | |
| | | | | | | | | | | W. Hayman | 6 | 10 | 2 | 0 | | | | | |
| | | | | K. A. McDougall | 4 | 3 | 6 | 6 | 6 | | | | | | | | | | |
| | | | | Robert Whitelock Phillips | 6 | 6 | 2 | 3 | 4 | | | | | | | | | | |