Champion Flat jockey Richard Hughes took the lead in the title race for the first time this season when completing a double at Salisbury.
The 41-year-old leads Ryan Moore by 145 wins to 144 after scoring on Elysian Flyer and Musicora.
He said: "It's a pleasure to go by the best jockey in the world. I know he's not trying [to be champion], but I am."
Moore has indicated he is likely to ride abroad for the final days of the season, which finishes on 8 November.
Hughes, who is seeking a third straight title, missed the start of the campaign in March after breaking his back in a fall in Dubai.
Moore was champion in 2006, 2008 and 2009. The 31-year-old has said he would like to win the title again, but that it was not his sole ambition for the season.