Frankie Dettori rode a 55-1 treble at Wolverhampton on Thursday to go further clear in his fight with Kieren Fallon to win the jockeys' title.
Defending champion Fallon also landed a double at Dunstall Park, but the gap between the pair has stretched to eight, with Dettori leading 174 to 166.
Dettori triumphed on Cloonavery and Forzeen, both trained by Jamie Osborne, plus Nautical for Tony Carroll.
Fallon claimed the first and last races with Watchmyeyes and Blythe Spirit.
Bookmakers cut Dettori's odds further for the title, and he is now 2-9 from 2-7 with
Ladbrokes, the shortest price he has been all season.
"You just have to take it a day at a time. I've got great respect for Kieren,
he's a fantastic jockey, and we are both doing our best," said the Italian.
Dettori has not won the Flat jockeys' championship since consecutive wins in 1994 and 1995, while Fallon has claimed six of the last seven titles.