Head to Head
| Tour Championship 2022 | 2022/03/30 12:00 | Ronnie O'Sullivan v Mark Williams | 10-9 |
| Welsh Open 2021 | 2021/02/20 19:10 | Mark Williams v Ronnie O'Sullivan | 1-6 |
| Championship League Snooker | 2021/02/11 15:45 | Ronnie O'Sullivan v Mark Williams | 1-3 |
| World Championship 2020 | 2020/08/11 18:00 | Mark Williams v Ronnie O'Sullivan | 10-13 |
| Gibraltar Open 2019 | 2017/11/16 11:30 | Ronnie O'Sullivan v Mark Williams | 5-1 |
| UK Championship | 2016/12/02 19:00 | Mark Williams v Ronnie O'Sullivan | 2-6 |
| Championship League Snooker | 2016/01/04 12:00 | Ronnie O'Sullivan v Mark Williams | 3-2 |
Home History
| The Masters 2023 | 2023/01/10 19:00 | Mark Williams v David Gilbert | 6-2 |
| English Open 2022 | 2022/12/16 12:00 | Neil Robertson v Mark Williams | 5-3 |
| English Open 2022 | 2022/12/15 19:00 | Barry Hawkins v Mark Williams | 2-4 |
| English Open 2022 | 2022/12/15 13:00 | Matthew Selt v Mark Williams | 0-4 |
| English Open 2022 | 2022/12/13 15:55 | Dominic Dale v Mark Williams | 2-4 |
| English Open Qualifiers 2022 | 2022/12/12 20:55 | Mark Williams v Matthew Stevens | 4-3 |
| Scottish Open 2022 | 2022/12/01 19:00 | Mark Williams v Joe O'Connor | 3-4 |
| Scottish Open 2022 | 2022/11/30 21:00 | Jimmy Robertson v Mark Williams | 0-4 |
Away History
| The Masters 2023 | 2023/01/09 13:05 | Ronnie O'Sullivan v Luca Brecel | 6-1 |
| English Open 2022 | 2022/12/15 13:00 | Martin Gould v Ronnie O'Sullivan | 4-1 |
| English Open 2022 | 2022/12/14 13:00 | Dechawat Poomjaeng v Ronnie O'Sullivan | 2-4 |
| English Open Qualifiers 2022 | 2022/12/12 19:00 | Ronnie O'Sullivan v Ben Mertens | 4-3 |
| Scottish Open 2022 | 2022/11/30 19:00 | Gary Wilson v Ronnie O'Sullivan | 4-3 |
| Scottish Open 2022 | 2022/11/29 19:00 | Ben Woollaston v Ronnie O'Sullivan | 2-4 |
| Scottish Open Qualifiers 2022 | 2022/11/28 19:00 | Ronnie O'Sullivan v Bai Langning | 4-0 |
| UK Championship 2022 | 2022/11/18 13:05 | Ding Junhui v Ronnie O'Sullivan | 6-0 |