LONDON (Reuters) - Woe betide any ticket holder who got stuck in the queue for an ice cream at the O2 Arena on Monday -- the action might have been all over by the time they returned to their pricey seat.
Stanislas Wawrinka pummeled Tomas Berdych 6-1 6-1 in 58 minutes, then the evening's main course turned into fast food as world number one Novak Djokovic needed two minutes less to send newcomer Marin Cilic packing.
Defending champion Djokovic, who also won 6-1 6-1, can clinch the year-end number one ranking if he wins his next two Group A matches and few would bet against the Serb doing that.
As for Berdych and Cilic, they have a day to lick their wounds before meeting on Wednesday in a match both must win to keep their hopes of reaching the semi-finals alive.
Monday's singles were the most one-sided contests since the Tour Finals arrived in London in 2009 when eight of the 12 round-robin matches went to three sets.
None of the four singles matches so far have gone the distance and organizers and fans alike will be hoping for some excitement in the days to come.
Djokovic extended his winning streak indoors to 28 matches with a clinical demolition of U.S. Open champion Cilic, one of three debutants at the season-ender.
Cilic won the first five points but what happened next was painful viewing for fans of the 26-year-old, including the Croatian soccer team who arrived during the first set to cheer their man.
Djokovic picked him apart with relish, claiming his 11th victory over Cilic in 11 meetings and sending out a reminder to the newest member of the grand slam club that the ruling class are not ready to roll over yet.
"It's been a great, great match," Djokovic, who barely broke sweat, said on court. "I haven't played here for 12 months, it's great to be back. It was a great performance.
"Marin as a U.S. Open winner has a lot of confidence, but I managed to neutralize his serve and get a lot of ball back in play and that was part of the tactic."
Wawrinka, who like Cilic also won his first grand slam this year in Australia, has been flitting in and out of form since beating Rafa Nadal in Melbourne and since losing in the quarter-finals of the U.S. Open had chalked up only one victory.
But his free-flowing game returned with a vengeance against the hapless Berdych whose timing was badly off.
"I didn't expect to win that easy for sure," Wawrinka, who made the semi-finals here last year on his tournament debut, told reporters. "But I was ready to play well.
"I had a great week of preparation. Today, the start of the match was really important. That changed it completely."
He came within a point of winning the opening set 6-0 but was thwarted by a Berdych ace.
His opponent could not turn the tide, however, and Wawrinka wrapped up victory before the hour mark.
Berdych, who has now lost his opening match here five years in succession, said he faced "mission impossible" to reach the semi-finals although Djokovic's drubbing of Cilic could give him hope in the group permutations.
"Unfortunately, it was my worst match of the whole season, and I kept it for the start here in the World Tour Finals," Berdych told reporters."
In doubles play, American top seeds Bob and Mike Bryan, were surprisingly beaten by Lukasz Kubot (Poland) and Robert Lindstedt (Sweden) while third seeds Alexander Peya (Austria) and Bruno Soares (Brazil) edged out Jean-Julien Rojer (Netherlands) and Horia Tecau (Romania) in a deciding tiebreak.
Editing by Ed Osmond