He appeared on 7 December 2018 against Mark Jeary and won with a strong 110 points. He then won the last 3 games of the series, and was placed aside for the series finals. He returned to Countdown on 23 January 2019 to continue his run in Series 80, following Championship of Champions XV, and here he wrapped up his unbeaten run, joining the 800 club in the fourth show of the new series.
Whitehurst's aggregate score of 821 points secured him a spot in the Series 80 finals in June as the number 3 seed. In his quarter-final, he took on Steven Turnbull and fell behind fairly early due to the latter's darrenic pair of EARWIGS and HOOLIGAN. However, he then mounted a strong comeback during the third "half" and solved the final six-small numbers round to go into the conundrum with a 1-point advantage, and after neither player unscrambled RINGACHED in the time, he therefore advanced to the semi-finals.
|#||Date||Type||Contestant 1||Score||Contestant 2||Guest||Lex||Max|
|6969||7/12/2018||P||Mark Jeary||85 – 110||Brendan Whitehurst||Nicki Chapman||Susie Dent||126|
|6970||10/12/2018||P||Brendan Whitehurst||96 – 59||James Fenn||Dan Walker||Susie Dent||133|
|6971||11/12/2018||P||Brendan Whitehurst||104 – 50||Sam Reilly||Dan Walker||Susie Dent||117|
|6972||12/12/2018||P||Brendan Whitehurst||92 – 83||David Rutherford||Dan Walker||Susie Dent||124|
|6995||23/01/2019||P||Brendan Whitehurst||104 – 62||Linda Nowotarski||Suzannah Lipscomb||Susie Dent||127|
|6996||24/01/2019||P||Brendan Whitehurst||107 – 52||Laurence Dunkling||Suzannah Lipscomb||Susie Dent||137|
|6997||25/01/2019||P||Brendan Whitehurst||112 – 62||Charlotte Aldworth||Suzannah Lipscomb||Susie Dent||125|
|6998||28/01/2019||P||Brendan Whitehurst||96 – 44||Vittorio Angelone||Suzannah Lipscomb||Susie Dent||126|
|7103||24/06/2019||QF||Brendan Whitehurst||58 – 57||Steven Turnbull||Rufus Hound||Susie Dent||146|