| Result | Tournament |
|---|---|
| Mason Stewart defeated Mark Showalter | 2024 Derby City Classic One Pocket |
| Mark Showalter defeated Tracy Cantrell | 2023 Derby City Classic Bank Pool |
| Mark Showalter defeated Tony Flannery | 2023 Derby City Classic Bank Pool |
| Kim Dyer defeated Mark Showalter | 2023 Derby City Classic Bank Pool |
| Mark Showalter defeated John Braud | 2023 Derby City Classic 9-Ball |
| Joe Johnson defeated Mark Showalter | 2023 Derby City Classic 9-Ball |
| Mark Showalter defeated Warren Kiamco | 2019 U.S.Open 9-Ball |
| Jui-An Hsu defeated Mark Showalter | 2019 U.S.Open 9-Ball |
| Bradley Shearer defeated Mark Showalter | 2019 U.S.Open 9-Ball |
| Peter Hetherington defeated Mark Showalter | 2012 U.S.Open 9-Ball |
| Mark Showalter defeated Eddie Cirasella | 2012 U.S.Open 9-Ball |
| Warren Kiamco defeated Mark Showalter | 2012 U.S.Open 9-Ball |