Six-time champion Ernie Els trounced Colin Montgomerie 6&5 in their 36-hole first-round match of the HSBC World Match Play at Wentworth.
Els is targeting a seventh World Match Play title
Defending champion Paul Casey romped to a 3&2 win against American Jerry Kelly but Open champion Padraig Harrington crashed out 4&2 to Dane Anders Hansen.
England's Justin Rose also lost 5&4 to American Hunter Mahan.
US Open champion Angel Cabrera of Argentina was on good form to down South Africa's Retief Goosen 6&5.
Dane Soren Hansen came back from one down after 18 to beat South African Rory Sabbatini 4&3.
I was just rubbish all day - rubbish
Sweden's Henrik Stenson was level with American Woody Austin with one hole left before play was suspended for the light and set to resume at 0800 BST on Friday.
Argentine Andres Romero, who led the Open before finishing double-bogey, bogey, led Swede Niclas Fasth by two after 32 holes.
In the second round, Casey will take on Cabrera, Els will play either Fasth or Romero, Soren Hansen will meet Mahan and Anders Hansen will face either Stenson or Austin.
Wentworth local Els was never headed and from the seventh onwards never less than two up against three-time PGA Championship winner Montgomerie.
Montgomerie was a shadow of his Ryder Cup self
The world number five surged to five up after 18 and reached seven up four holes later, though Montgomerie battled to keep the game alive until the 31st hole.
"I feel kind of sad beating Colin in the first round," said Els, who is planning to go to Paris on Sunday for the Rugby World Cup semi-final between South Africa and Argentina which kicks off at 2000 BST.
"We've had so much success around this course and in this event. I think it would have been a really great match later in the tournament."
Montgomerie, the 1999 champion who lost to Els in the 1994 final and twice in US Open play-offs, admitted: "I was just rubbish all day - rubbish."
Casey, who beat American Shaun Micheel 10&8 to win £1m last year, was never behind over the first 18 holes.
But he saw a three-shot lead after six whittled back to level after 12 before surging three ahead again on 18.
In the afternoon, he reached five up after eight but Kelly reduced the deficit to two holes at the 15th before Casey ensured his clash against Cabrera with a birdie on 16.
Casey beat Shaun Micheel 10&8 to win £1m last year
"I hope I can bore him to death - down the fairway, on the green, lots of birdie chances," said Casey.
"He will be 20 yards ahead of me, but I just have to be more consistent than he is.
"I'm going to have to play better golf than I did today. I feel very lucky."
Harrington struggled and was chasing reigning PGA champion Hansen from the eighth hole of their first round.
"It's really disappointing because I was hoping to go all the way," said the Dubliner, who could now lose his position at the top of the European Order of Merit.
Cabrera, who won the PGA Championship over the West Course in 2005, said: "Everything felt very good and I always love being here at Wentworth.
"From the moment I stepped on the first tee and hit my first shot down the middle I felt good."
Round one results (36 holes):
(1) Paul Casey (Eng) beat (16) Jerry Kelly (US) 3&2
(8) Retief Goosen (SA) lost 6&5 to (9) Angel Cabrera (Arg)
(5) Justin Rose (Eng) lost 5&4 to (12) Hunter Mahan (US)
(4) Rory Sabbatini (SA) lost 4&3 to (13) Soren Hansen (Den)
(3) Padraig Harrington (Ire) lost 4&2 to (14) Anders Hansen (Den)
(6) Henrik Stenson (Swe) all square after 35 holes against (11) Woody Austin (US)
(7) Niclas Fasth (Swe) 2 down after 32 v (10) Andres Romero (Arg)
(2) Ernie Els (SA) beat (15) Colin Montgomerie (Sco) 6&5