Five things to watch, US Open Day 12: Medvedev's fitness; Cabal-Farah

The men's semifinals plus the men's doubles final will be played out on Friday at the US Open. These are five storylines to look out for on Day 12 in New York.

Rafael Nadal is primed to capture his fourth US Open trophy, and 19th career Grand Slam title. To get there, he will first have to go through the hard-hitting Matteo Berrettini, who is making a serious run as the ATP’s most improved player. Nadal is locked in; he is the only remaining major title winner left in the draw, and when that happens, he makes it count. This is the fifth time Nadal has been the last remaining “Big Four” member in the semifinals—he has won the title the previous four times. Not only was he victorious, he won 24 of 25 sets. According to the oddsmakers, it will take a miracle for Berrettini to defeat Nadal. The Spaniard is a gargantuan favorite in his first ever matchup with the 6’5” Italian.

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Somehow Daniil Medvedev is still standing, and still crushing his competition. The 23-year-old Russian has played more tennis than anyone this summer. Before the tournament, he had played more US Open series matches than Federer, Nadal, and Djokovic combined. He will have his work cut out for him in his semifinal matchup against Grigor Dimitrov, who has finally found his former Top-5 level. Dimitrov was brilliant in his first career victory over Roger Federer, and at this point in the tournament, will be fitter and fresher than Medvedev. Dimitrov has made the most of a favorable draw, including a walkover from No. 12 seed Borna Coric. Medvedev is the favorite in this matchup, but his body is slowly but surely breaking down. Although Medvedev received a full two days off after his quarterfinal win, Dimitrov could once again capitalize on an ailing opponent, who is practically mummified from all the athletic tape wrapped on his body.

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Despite her three-set loss to Bianca Andreescu, Elise Mertens will leave New York with her head held high—and possibly a trophy. The Belgian is pulling double duty this week, advancing to the quarterfinals of singles and semifinals of doubles. Mertens and partner Aryna Sabalenka have been crushing the competition this week and haven’t lost a set en route to the final four. The two will face off against the somewhat surprise team of Vania King and Caroline Dolehide. The American duo combines youth and power with savvy and championship experience. In 2010, King won two Grans Slam titles with partner Yaroslava Shvedova. Dolehide crushes the ball, while King provides some of the best hands in the game. Mertens and Sabalenka, winners of the 'Sunshine Double' at Indian Wells and Miami, are strong favorites in this match, but the rowdy pro-American crowd will do their best to lift King and Dolehide into the final round.

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The top-seeded team of Juan Sebastian Cabal and Robert Farah will look to win their second consecutive Grand Slam title on Friday against Marcel Granollers and Horacio Zeballos. The Columbian duo won Wimbledon in July, and spent the following two weeks enjoying the fruits of their labor. “It was totally crazy, just insane how much love the (Colombian) people gave to us, Farah said. “We even went to the president’s house. Granollers will look to use his experience to capture his first Grand Slam title; he lost in the final of both the French Open and US Open in 2014 with countryman Marc Lopez. Zeballos has no prior Grand Slam final experience to speak of, but with a win, could become the first Argentinian man to win a major doubles title. The Colombians will attempt to be the second consecutive team to win the Wimbledon/US Open double, a feat Jack Sock and Mike Bryan accomplished last year.

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Americans Brandon Nakashima and Emilio Nava continue to lead the way for the American juniors on the boys side. Nakashima currently competes for the University of Virginia Cavaliers. Nakashima has tasted some pro circuit success, reaching a career-high ATP singles ranking of No. 523 earlier this year. Nava, this year’s Australian Open finalist, also enjoyed some ATP level success, maxing out his career-high ranking earlier this year at No. 464. Nava is also American tennis player Ernesto Escobedo’s cousin.

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Wake up every morning with Tennis Channel Live at the US Open, starting at 8 a.m. ET. For three hours leading up to the start of play, Tennis Channel's team will break down upcoming matches, review tournament storylines and focus on everything Flushing Meadows.

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