Lewis has won four of his 11 matches in the Premier League in 2010
Adrian Lewis has dropped to sixth in the Premier League table after losing 8-3 to Mervyn King in Liverpool.
The Stoke-on-Trent player is two points behind fourth-placed James Wade with three matches left to play.
Defending champion Wade moved into the top four for the first time with a 8-3 victory against Raymond van Barneveld, who is now bottom of the table.
Meanwhile, Premier League leader Phil Taylor maintained his unbeaten record in 2010, defeating Simon Whitlock 8-5.
The four-time winner of the event, who has already qualified for the semi-finals at Wembley on 23 May, sealed victory with a 125 finish.
"I'm pleased with my performance and I'm getting back to my best now, which is important because we're getting down towards the play-offs and the time of year where there's a lot of money to be won," said Taylor.
Terry Jenkins beat Ronnie Baxter 8-4 in the other match in week 11 of the competition.