In the first leg of the second set, the Japanese player stole the point and went two legs ahead.
Ashton then pulled a leg back to give herself a chance in the second leg, and levelled at 2-2.
Sukuzi: I can't believe I've retained the title
Suzuki, the pre-match underdog even if she was defending her title, claimed the final leg of the set to go 2-0 up.
In the first leg of the third set, Ashton’s problems were compounded when she saw one dart bounce off the board, allowing Suzuki an immediate break before the number one seed broke back and established a 2-1 lead until the second seed levelled.
That took the game to the latest time that any match had been played so far - 22:40 - and Ashton required a win to stay in the game.
The match ended in Suzuki’s victory when she seized on a profligate final leg from her opponent to seal a whitewash.
'It's there!' - See how Suzuki defended BDO World title