NEW YORK - Comeback girl Kim Clijsters, in a controversial win, thrashed the frustrated defending champion Serena Williams 6-4, 7-5 to power into the final of the US Open.

The match ended in unorthodox fashion Saturday, with the furious Williams calling for a foot fault to yield a match point to the Belgian. Williams then exploded at a line judge to draw a point penalty and the loss.

In the last game, the American got into an altercation with a line judge who called the foot fault and was eventually assessed a second code violation - she got her first by smashing a racket after losing the first set - to end the match on a sour note.

Williams was warned for cursing the lineswomen, with tournament referee Brian Early called to the court, thus marking a bitter end.

“She was called for a foot fault, and she said something to a line umpire which was reported to the chair,” said Early, “That resulted in a point penalty for unsportsmanlike conduct that happened to be on the match point.”

Williams tried to play down the incident.

“Today was tough, I didn’t play my best, I had more errors today than all my matches combined. Kim played really well and came out with a big plan.

“I don’t have any regrets, I was out there, I fought and tried. I did my best. I’m intense and give 200 percent in everything I do. I just go for it,” Williams said.

Clijsters, who stepped away from the game for more than two years for marriage and motherhood, will play the New York final Sunday night four years after her last appearance at Flushing Meadows when she won the title, her only Grand Slam crown.

She will face Danish ninth seed Caroline Wozniacki, who beat fellow teenager Belgian Yanina Wickmayer 6-3, 6-3.

Clijsters was in shock after the bizarre ending. “I was trying to focus on the match point.

“As I started to get ready for return, I saw Serena talking to lineswoman. I was too far away to hear what was going on.”

The 26-year-old Belgian had lost seven of eight previous matches to Williams. “I tried to focus on one point at a time. I came out really well, seeing the ball really well.

“I kept her on the back foot. She had a few games when she served really well. You have to forget about those and re-focus. That’s what I did, I’m still in shock. I never dreamed that I’d be in another final here.”

Both women came out more than ready for action after waiting more than eight hours to take to the court after a horror 48 hours of rain delays which has already wrecked the tournament schedule and forced the men’s final to a Monday for the second year in succession.

Williams, the second seed struggling to re-take the number one ranking, was comprehensively outplayed, with 31 unforced errors.

Rafael Nadal buried his growing US Open weather frustration Saturday to finally complete a marathon quarter-final, crushing Fernando Gonzalez 7-6(4), 7-6(2), 6-0 in a men’s match which began Thursday.

The contest was completely rained off Friday, a development which resulted in the men’s final being postponed to Monday for the second year in a row at the hard-luck major which still has no plans for a covered showcase court.

Nadal will now have to play three days in succession if he is to fulfill the dream of completing his career Grand Slam.

The Spaniard who is nursing an abdominal strain will play a semi-final Sunday against Argentine Juan Del Potro, who booked his place in the last four Wednesday.

Nadal said that Friday’s enforced day off gave his abdominal muscles some healing time.

“That might have helped me to recover a bit better. I felt good today. Fernando had some errors today which helped me,” he said.

“I’m in the semi-finals now and I hope to keep doing well.”