In the third of a special series of interviews with Roger Federer at home in Switzerland, the 35 year old reveals what makes the US Open fans so special.

The Swiss, a five-time champion at the US Open, also gives his opinion on how the new roof on Arthur Ashe Stadium would raise the level of play, especially in the latter stages of the tournament. 

A lot can happen in 10 years, but little has changed for Novak Djokovic at the US Open. As it has been the case for every year since 2007, the Serbian is into the last four at the year’s final Grand Slam event. American tennis legend Jimmy Connors holds the record with 12 straight semi-final showings.

“I put myself in a position again to be one match away from the final. As the tournament progresses, I feel like I’m getting better,” Djokovic said. “I’m reaching my peak in terms of my form.”

The World No. 1 and defending US Open champion advanced on Tuesday night when Jo-Wilfried Tsonga retired due to a knee injury, with Djokovic leading 6-3, 6-2. He first announced himself to the New York crowd with a run to the final in 2007 (l. to Federer), then captured the title in 2011 (d. Nadal) and 2015 (d. Federer).

Even if fully healthy, Tsonga would have had his hands full with the in-form Djokovic. The Serbian won their first tour-level meeting to claim his maiden Grand Slam title at the Australian Open eight years ago and came into the match with a 15-6 lead in their FedEx ATP Head2Head rivalry. In the two sets played on Tuesday night, Djokovic once against used his superior defensive acumen to nullify Tsonga’s booming inside-out forehand, and guided his two-handed backhands down the line to exploit the Frenchman’s court positioning.

Djokovic amassed 18 winners and 12 unforced errors during the abbreviated match, while Tsonga, frequently going for broke due to his impaired movement, hit 11 winners and 36 unforced errors. One of the best returners in the game, the Serbian won 18 of 25 points when facing the Tsonga second serve.

In the semi-finals, Djokovic will face Gael Monfils for the 13th time at tour-level. The FedEx ATP Head2Head matchup has been a favorable one for Djokovic over the years. He leads the series 12-0 and has not dropped a set to the Frenchman in more than two years.

“I love watching Gael,” Djokovic said. “He’s one of the players that I will definitely pay a ticket to watch. He’s very charismatic. He plays with a smile. He enjoys tennis and enjoys life. In my eyes, this is what everybody is supposed to be like, whether you’re a sportsman or not. Bring that smile; bring that good energy. That’s why people like him. 

“But also, he seems more focused at this time of his career. Especially on the hard court this year, he’s playing the best tennis he’s ever played. He’s very consistent. He hasn’t dropped a set before the semis. That says a lot about the level he’s at. Definitely expecting a tough battle.”

New York tennis fans deserved no less during the final match on Louis Armstrong Stadium: Five-time US Open champions Bob Bryan and Mike Bryan facing off against eighth seeds Feliciano Lopez and Marc Lopez (no relation), the team that denied the Bryan brothers their 17^th Grand Slam title earlier this season at Roland Garros.

Just like the earlier edition, Tuesday’s quarter-final contest went the distance. And just like the June meeting, the Spaniards walked away victorious, moving into their first semi-final in Flushing Meadows 7-6(2), 4-6, 6-3.

“It was very special for us to beat the Bryans. They are the best players in the history of the game,” Feliciano Lopez said on court after the match.

The 34-year-old Spaniards, who started playing together this season, will try to reach their fourth final of the year when they play compatriots Pablo Carreno Busta and Guillermo Garcia-Lopez or 12^th seeds Lukasz Kubot and Alexander Peya in the semi-finals.

Lopez/Lopez won almost 75 per cent of their first-serve points during the quarter-final match. But the third-seeded Bryan brothers actually won one more point than the Spanish duo – 98 to 97.

“There were a lot of tight moments during the match,” Feliciano Lopez said. “It’s difficult but somehow we managed to win the match and we’re very happy for that.”

Read: ATP World Tour Honours 18-Time Doubles Champion Eric Butorac

The match was the final contest in the history of the Louis Armstrong Stadium at the USTA Billie Jean King National Tennis Center. The USTA plans to demolish the stadium shortly after this year’s US Open. A new stadium, with a roof, is expected to be ready in time for the 2018 US Open.

“Everything today was very special and very emotional,” Feliciano Lopez said.

Friendships don’t matter when you step onto a tennis court. Lucas Pouille had taken out Rafael Nadal in a dramatic five-set battle in the US Open fourth round. But it came at a price. With Pouille fatigued, his good friend and countryman Gael Monfils showed no mercy, reaching his first US Open semi-final with a resounding 6-4, 6-3, 6-3 victory on Arthur Ashe Stadium.

“I’m happy with my performance. I think it is never easy to play a quarter-final against a French guy. I think I handled it pretty good mentally,” Monfils said. “I’m happy with that and where my game is.”

It could be an all-French affair again in the semi-finals, but World No. 1 Novak Djokovic still holds the power to deny a French finalist at Flushing Meadows. The Serbian takes on Jo-Wilfried Tsonga in the night session, with the winner to face Monfils in the last four. It is the first time in the Open Era that three Frenchmen have reached the quarter-finals of the same Grand Slam event.

“I think we all work hard, and somehow we make it in the same moment,” Monfils said.

The 10th-seeded Monfils has been untouchable so far in New York. The Frenchman, who celebrated his 30th birthday last week, has won all 15 sets in his campaign and has compiled a 19-2 record on hard courts since Wimbledon.

Working with Mikael Tillstrom this season, Monfils has produced one of his career-best campaigns. The Frenchman is in strong contention to qualify for the Barclays ATP World Tour Finals for the first time after winning his sixth ATP World Tour title in Washington (d. Karlovic) and reaching the finals in Monte-Carlo (l. to Nadal) and Rotterdam (l. to Klizan). Monfils is currently eighth in the Emirates ATP Race to London, with the top eight players at the end of the regular season set to compete at The O2.

“My health has been big trouble all my career, and now it is somehow stabilized,” Monfils said. “I think it helps me a lot to be stronger.”

Watch Monfils Uncovered

Monfils is through to his second Grand Slam semi-final after improving to 2-6 in major quarter-finals. Since his first semi-final at Roland Garros eight years ago, the Parisian had suffered six successive defeats at this stage. 

But he was in a ruthless mood as he dismissed Pouille’s challenge in just over two hours. The ailing Pouille desperately searched for the high-quality tennis that saw him topple Nadal two nights earlier, but just came up short. The 23 year old, contesting his second Grand Slam quarter-final of the season, committed 44 unforced errors, compared to only 15 from Monfils, and won just 33 per cent of points behind his second serve.