MOHALI, India (AP) - The tense buildup to what has been billed as "the mother of all World Cup matches" came to a spine-tingling climax on Wednesday when Sachin Tendulkar strode out to bat for India with Virender Sehwag.

Hundreds of people moved into their seats as soon as the gates opened, four hours before the blockbuster semifinal between archrivals India and Pakistan was due to begin. The match was sold out last week, but incredibly there were still a few ticket-holders missing as the match began due to intensive security checks at all entrances. The 28,000 tickets for the match were the most sought-after on the subcontinent.

Tendulkar, seeking his 100th international century, and Sehwag were greeted by a tumultuous roar as they walked out onto the pitch at the Punjab Cricket Association Stadium.

Watching them was a host of Bollywood superstars, dignitaries and high-ranking politicians - including the Prime Ministers of both countries in what is being seen as a possible first step toward improved diplomatic relations between India and Pakistan.

Indian premier Manmohan Singh and Pakistan counterpart Yousuf Gilani were warmly cheered by the crowd as they walked onto the pitch following the national anthems. Singh shook hands with the Pakistan players before Gilani, while the roles were reversed as the pair met the India team.

With the two premiers in attendance, security was inevitably tighter than at any other match. Roads around the fortified stadium were closed, and anyone entering the ground had to negotiate several checks, with bags being meticulously searched for any dangerous or suspicious objects.

Police and soldiers on foot, on horse back and armored vehicles patrolled the fortified stadium, where a crush of fans had gathered. The sporting rivalry between the nations is as intense as any, but the match took on an added political significance when Gilani accepted Singh's invitation to watch with him.

"I am going there to show solidarity with our team, with their team and to promote cricket," Gilani said.

While the historic meeting occurs in the VIP box at the PCA Stadium, the sellout crowd had their eyes trained on the pitch, most of those eagerly hoping national sporting icon Tendulkar can score a century. There were small pockets of Pakistan fans waving the green and white flag, but they were almost invisible in a sea of Indian supporters. Tendulkar, whose face adorns posters across the city, was dismissed for 99 by fast bowler Umar Gul in his last match against Pakistan at Mohali in 2007.

India defeated Australia to set up the showdown with Pakistan and prompt a desperate scramble for tickets. The match has been sold out for more than a week but that didn't stop people queuing at the ticket office in the days before the match, hoping that more seats might be released.

On the black market, tickets reportedly fetched up to 100 times their face value.

Those who weren't fortunate enough to get their hands on a ticket watched on big screens set up around nearby Chandigarh, which came to a standstill for the game.

Police have also relaxed a ruling banning people living near the ground from climbing on their roofs to get a birds-eye view.

Businesses across the country shut down for the afternoon - in the knowledge that productivity would undoubtedly drop to zero anyway.

The government decreed a half day in Pakistan, meaning work stopped at noon so that people could watch the match.

KEY BISCAYNE, Florida (AP): Roger Federer advanced to the quarterfinals of the Sony Ericsson Open after beating qualifier Olivier Rochus 6-3, 6-1 in a match that ended at 1:29 a.m Wednesday.

Taking the court following a succession of marathon matches, Federer needed just 52 minutes to beat Belgian Rochus. A couple of thousand fans remained until the finish.

Federer couldn't remember ever starting a match so late. He found it odd even to be up at such an hour, given that he's the father of young twins.

"I'm getting up usually at 1:30," he said. "That's what tennis is all about. We don't know when we play, and we don't have a set schedule, and so we have to be able to adapt."

Federer's opponent Thursday will be No. 25-seeded Gilles Simon of France, who beat Serbian Janko Tipsarevic 4-6, 7-6 (3), 6-2.

Federer and Rochus took the court after Maria Sharapova earned a semifinal berth by winning a 3 1/2-hour match that ended at 12:19 a.m. She beat No. 26-seeded Alexandra Dulgheru of Romania 3-6, 7-6 (6), 7-6 (5).

Sharapova's opponent will be No. 21 Andrea Petkovic of Germany, who earlier played for nearly three hours on the same stadium court to notch her second upset in two days, beating No. 6 Jelena Jankovic 2-6, 6-2, 6-4. Petkovic eliminated No. 1 Caroline Wozniacki in the fourth round.

Two-time champion Kim Clijsters also went the distance, overcoming five match points to beat No. 19-seeded Ana Ivanovic of Serbia 7-6 (4), 3-6, 7-6 (5).

Seeded-seconded Novak Djokovic extended his winning streak to 23 consecutive matches by beating fellow Serb Viktor Troicki 6-3, 6-2 in the fourth round.

Also advancing to the quarterfinals was top-ranked Rafael Nadal, who committed only five unforced errors to beat No. 21-seeded Alexandr Dolgopolov of the Ukraine 6-1, 6-2.

Djokovic won two Davis Cup matches in December and is 21-0 in 2011, the best record to begin a year since Ivan Lendl started 25-0 in 1986. Djokovic beat Troicki for the ninth time in a row, with six of the victories since August.

Mardy Fish, the last American in the tournament, limped into the quarterfinals after a grueling 7-5, 7-6 (5) win over Juan Martin del Potro. Fish will next face No. 6 David Ferrer of Spain.

American John Isner, seeded 30th, lost to Kevin Anderson of South Africa, 6-3, 7-6 (4).

Kim Clijsters overcame five match points to beat No. 19-seeded Ana Ivanovic of Serbia, 7-6 (4), 3-6, 7-6 (5). Clijsters, the tournament champion in 2005 and again last year, was serving at 1-5, love-40 when her comeback begin.

Ivanovic took the loss badly.

"You should see my racket," the 2008 French Open champion said, managing a smile. "I kind of broke my racket, and then kind of cried a little bit, and then I was OK."

Sharapova won despite 17 double-faults and twice as many unforced errors as Dulgheru.

"It was long. It was tough," she said. "It was not my best performance, but, you know, I gutted it out till the end."

Sharapova turned her ankle late in the third set and required treatment from a trainer in the middle of a game. The crowd gasped when her misstep was replayed on the video scoreboard, but the injury didn't appear to affect her.

"It hurt when I did it," she said. "I iced it a lot, and did an ice bath and got it taped. I think I'll be OK. I'm tough."

Fish, 29, will overtake Andy Roddick and become the top-ranked American man for the first time if he defeats Ferrer.

"Being the No. 1 American would be something that would be pretty cool to tell my kids about," said Fish, who is married but not yet a dad.