Johanna Konta defeated fellow Briton Heather Watson in straight sets as the pair met for the first time on the WTA Tour, at Indian Wells.
Konta, the British No 1 and 11th seed, moved into the third round of the BNP Paribas Open with a 6-4 6-4 win on Stadium 1.
Their only previous meeting came four years ago in a second-tier event in Barnstaple which saw Watson retire injured after losing the first four games.
This time it reached a proper conclusion and Konta, ranked 97 places above her opponent, made her quality tell despite some tough moments.
Watson won the first two games of the match and put together three in a row at the death as Konta threatened to wobble, but there were too many mistakes of her own littered through the 94-minute encounter.
Watson double-faulted on nine occasions and at times grew visibly frustrated at her lack of control.
She was broken on five occasions in all, edged out of the first set then faced with a formidable 5-1 scoreline in the second.
The match appeared lost at that moment but Watson produced her best tennis of the day to take things deep, serving to love twice in a row and breaking in between.
The momentum finally gave way at the crucial moment and, following a good rally at match point, Watson failed to clear the net as Konta won through.
Meanwhile, Kyle Edmund will face Novak Djokovic in the second round of the men's event at Indian Wells after cruising past Portugal's Gastao Elias 6-1 6-3.
The 22-year-old from Beverley, Yorkshire, was unbroken throughout the 65-minute match and won against the serve twice in each set.
Djokovic was granted a bye through to the second round of the California event.