Phil Taylor sealed a Premier League play-off spot, but two Michael van Gerwen wins in Bournemouth cut his lead at the top of the table to two points.
Taylor beat Robert Thornton 7-2, while world number one Van Gerwen defeated Peter Wright by the same scoreline and then overcame Adrian Lewis 7-5.
Lewis also lost to Raymond van Barneveld, denting his play-off hopes.
He is just a point clear of James Wade, who drew 6-6 with third-placed Gary Anderson, in the final play-off spot.
Taylor, 55, has won the Premier League on six previous occasions, but he was not involved in the play-offs in 2015 - the first time he had failed to qualify since the event's inception in 2005.
Victory over Thornton stretched his unbeaten run in the tournament to 12 matches.
Van Gerwen will confirm his play-off place if he takes avoids defeat by Wade in Birmingham on 28 April.
Premier League - round 12 results
Michael van Gerwen 7-2 Peter Wright
Raymond van Barneveld 7-4 Adrian Lewis
Gary Anderson 6-6 James Wade
Phil Taylor 7-2 Robert Thornton
Adrian Lewis 5-7 Michael van Gerwen