Grand slam winner
A grand slam winner is a player who wins all his or her possible games of Countdown unbeaten. To become a grand slam winner, one must go undefeated in the heats, then win his or her series (becoming a xicount), and finally become the Champion of Champions.
To date, there have been six grand slam winners:
- Harvey Freeman won Episodes 459 through 466, the Series 10 finals, and Championship of Champions III. He also won the Supreme Championship. However, he was defeated by Mark Nyman in a contest from the short-lived Countdown Masters series.
- Nic Brown won Episodes 658 through 665, the Series 14 finals, and Championship of Champions IV.
- Don Reid won Episodes 1361 through 1368, the Series 25 finals, and Championship of Champions VII. However, he did lose to John Clarke in the Supreme Championship.
- Scott Mearns won Episodes 2553 through 2560, the Series 41 finals, and Championship of Champions X. His unbeaten record came to end in a special match.
- Graham Nash won Episodes 2813 through 2820, the Series 43 finals, and Championship of Champions XI.
- Zarte Siempre won Episodes 6774 through 6781, the Series 78 finals, and Championship of Champions XV. He previously won 5 heats in Series 69, and has more wins than any other grand slam winner (20).
An arguable case can be made that Conor Travers also qualifies as a grand slam winner, given that, in addition to becoming an octochamp and the champion of Series 54, he won the 30th Birthday Championship, which was held during a time when Championships of Champions were on hiatus. However, he had also participated, and been defeated, in CoC XII beforehand.
A grand slam winner is typically the #1 seed for his or her series. The only exception is Graham Nash, who was #2 seed behind David Williams.