Teen tennis star Andy Murray is set to be the British number one after beating South Africa's Rik de Voest in Memphis.
The two higher-ranking British players Tim Henman and Greg Rusedski have both suffered defeats in Rotterdam.
This means the Scottish teenager will move ahead of them when the rankings are published on Monday.
Henman has been Britain's number one since 1999, but Murray's improved performance over the past 12 months has finally ended his reign.
Murray took almost two-and-a-half hours to overcome 'lucky loser' Rik De Voest 7-6 (7-4) 3-6 7-5.
He now faces Sweden's Robin Soderling in the quarter-finals of the Regions Morgan Keegan Championships.
Murray played Soderling at the same stage in the San Jose Open, which he went on to win - his first major title.