World number one Roger Federer underlined his status as French Open favourite just before the unruly home crowd decided to steal the limelight on a rainy day at Roland Garros on Sunday.
Federer had hammered former champion Carlos Moya 6-1, 6-4, 6-3 to reach the quarter-finals when the fans stopped Spaniard Rafael Nadal, regarded by many pundits as the Swiss top seed's main rival for the title, from playing for nearly 10 minutes.
The 18-year-old Nadal had won the first set of his fourth round match against Sebastien Grosjean 6-4 and had just broken the Frenchman for a 1-0 lead in the second set when the booing and jeering started.
The fans packing centre court were annoyed with Argentine umpire Damian Steiner, who refused Grosjean's request to check a ball mark on the red clay during the last point of that game.
They started stamping their feet and gesturing with their thumbs down. The boos and whistles became louder as Nadal made several attempts to re-start the match.
Eventually, Grosjean had to ask the crowd to calm down before play could resume.
The 15,000 crowd were then delighted to see Grosjean win the second set 6-3 but Nadal, who never lost in cool, recovered to build a 3-0 lead in the third set when there was another break.
This time only the rain was to blame and the pair will resume battle on Monday.
Federer, chasing the only Grand Slam title to elude him, proved his ambitions were serious by crushing Spain's Moya in just an hour and 41 minutes in the first true test of his campaign.
The elegant 23-year-old, who has not dropped a set yet, played close to perfection until 14th seed Moya, who was hampered by a sore shoulder, bowed out by failing to return a blistering forehand on the third match point.
The Swiss said his impressive win was not that relevant because of Moya's physical problems.
"Not all that fantastic because he's injured," Federer said when asked to assess his form.
"With the problem in the shoulder...I think he is very disappointed to have to play like this. But it went fine."
The gifted Federer has the perfect game to shine on clay but has never advanced past the quarter-finals at Roland Garros and disappeared in the first round in two of the last three years.
He faces a seemingly easy passage through to the semi-finals as he now meets world number 90 Victor Hanescu of Romania, who overcame former Wimbledon finalist David Nalbandian 6-3, 4-6, 5-7, 6-1, 6-2.
If he beats Hanescu, Federer could then meet Nadal for a place in the final.
The opening match on the first week's final day had seen world number one Lindsay Davenport stage a remarkable comeback to beat Kim Clijsters 1-6, 7-5, 6-3 and reach the quarter-finals.
The only remaining American in either singles draw, top seed Davenport looked helpless in the first set and was 3-1 down in the second but she recovered to beat Belgian Clijsters for the first time in seven meetings.
"I'm really a little bit amazed I was able to pull that match out today," said Davenport.
Davenport, who has won every Grand Slam tournament but this one, took four weeks off the circuit before coming to Paris, her preparations including a vacation in Mexico.
The American, who has often struggled on the Paris clay with a semi-final appearance in 1998 her best result, will meet local favourite Mary Pierce for a place in the semi-finals.
The 30-year-old Pierce, who won here in 2000, kept the French flag flying after edging out eighth seed Patty Schnyder 6-1, 1-6, 6-4 to reach the last eight.
The French fans made life difficult not only for Nadal but also for Schnyder, who survived 10 match points in a hostile atmosphere before bowing out.
"I've been playing wonderful shots, and it felt just like a funeral in that second set," the Swiss player said of the crowd's coolly biased reaction to her comeback.
Fourth seed Elena Dementieva, a runner-up here last year, disappeared just before the rain, fellow Russian Elena Likhovtseva beating her 7-6, 5-7, 7-5.
The rain break disrupted the day's programme and meant several big names, notably Wimbledon champion Maria Sharapova, Belgium's Justine Henin-Hardenne and men's title holder Gaston Gaudio of Argentina, will find out only on Monday if their Paris adventure takes them to the quarter-finals.