A forensic accountant has become the first female Countdown champion in 26 years.
Fiona Wood prevailed in the series final on Friday after correctly identifying the conundrum word as "lassitude", meaning a state of physical or mental weariness.
The programme, which has been on Channel 4 since the broadcaster launched in 1982, had not had a female champion since 1998.
After being presented with the trophy, Wood, 50, from Kinross, Scotland, said: "I just can't believe it. I'm not known for being decisive, and I thought long and hard before I decided to apply, and I'm just so glad that I did."
She said she applied after the show's host, Colin Murray, and the lexicographer Susie Dent appealed for older contestants and more women.
She added: "I have absolutely no regrets about applying and would encourage other women to give it a go."
In the final between Wood and Chris Kirby, Kirby attempt's at an eight-letter word score, "promotee", to usurp Wood's "promote" was unsuccessful as it was not in the dictionary. But Kirby came back by succeeding in another words round with "routeing".
The competitors continued to match each other, at one point getting the same word, opiates, during the tense 90th series final. But after answering the final conundrum, Wood's score was 96 to Kirby's 89.
Applications for women have soared after appeals from Murray, Dent and the mathematician Rachel Riley, Channel 4 said.
Dent, who has appeared in the programme's dictionary corner since 1992, said: "Fiona delighted us all and gave us one of the very best moments in our 42-year history. This series also reminded us how much Countdown is a show for everyone, and we would encourage anyone who loves the game to apply."
The guest in the studio was the actor and 2007 I'm A Celebrity winner, Christopher Biggins, who called the final "magical".
The first series of Countdown was won by Joyce Cansfield, a crossword compiler. Since then, four more women have won series: Hilary Hopper in 1987, Liz Barber in 1990, Verity Joubert in 1995 and Kate Ogilvie in 1998.
Murray was named as the permanent host of Countdown last year, taking over from the former Weakest Link host Anne Robinson.
Adapted from the French TV series Des Chiffres Et Des Lettres (Numbers and Letters), Countdown was originally hosted by Richard Whiteley. Nick Hewer, Des Lynam, Des O'Connor and Jeff Stelling have also served as presenters.