SHEFFIELD - Ronnie O'Sullivan established a 10-7 lead over fellow Briton Ali Carter on the first day of the world snooker championship final on Sunday.

O'Sullivan, bidding to win his fourth world title, compiled breaks of 141 and 117 on his way to going 5-3 up at the end of the opening session.

The evening session was a lower-scoring affair but O'Sullivan remained in front.

Carter, beaten by O'Sullivan in his only previous appearance in the final four years ago, battled to try and rediscover his top form.

Failing to match his opponent's impressive potting, Carter also struggled for position on occasions.

A fluked red helped Carter clinch the final frame of the day, leaving O'Sullivan with a three-frame lead.

The best of 35 frames match plays to a finish on Monday.