Defending Premier League champion Gary Anderson defeated protege Michael Smith 7-3 in Nottingham to earn his third successive win in the 2016 event.
Anderson, 45, shares the same manager as Smith and has acted as a mentor for the 25-year-old from St Helens.
Anderson is four points behind Premier League leader Michael van Gerwen.
Van Gerwen, who won his second UK Open title on Sunday, beat Dave Chisnall 7-2 with an average above 113, while Phil Taylor beat Robert Thornton 7-0.
Taylor's whitewash win against Thornton ensured he would be level on points with Van Gerwen at the top of the table before the pair meet in the next round of fixtures in Glasgow on 17 March.
Adrian Lewis defeated Peter Wright 7-3 on Wright's 46th birthday, while James Wade beat Raymond van Barneveld 7-5 in the other match in round six.
Premier League results - round six
Michael Smith 3-7 Gary Anderson
Peter Wright 3-7 Adrian Lewis
Raymond van Barneveld 5-7 James Wade
Robert Thornton 0-7 Phil Taylor
Dave Chisnall 2-7 Michael van Gerwen