Roger Federer, 2017 US Open
Tennis - US Open - New York, U.S. - August 29, 2017 - Roger Federer of Switzerland in action against Frances Tiafoe of the United States during their first round match. Reuters / Shannon Stapleton

World No. 3 Roger Federer was pushed to five sets by American teenager Frances Tiafoe in the first round of the 2017 US Open on Tuesday. Federer won the match 4-6, 6-2, 6-1, 1-6, 6-4 to advance to the next round.

The Swiss Master has already dropped two more sets at Flushing Meadows than he did during his fortnight en route Grand Slam No. 19 at Wimbledon. There are some realistic concerns about Federer's recent back injury. Federer was forced to withdraw from the Cincinnati Masters, the final stop before the US Open, after tweaking his back during his Rogers Cup final loss to Alexander Zverev.

Federer has acknowledged that the injury hampered his typical preparation for a Grand Slam event. And the third-seeded star is hoping to regain his rhythm and fitness over the course of the next few weeks. “I didn’t have the preparation I was hoping to get. I always knew I was going to come in feeling rusty or not great," Federer told reporters after Tuesday's victory.

2017 US Open: Roger Federer looking for Grand Slam No. 20

The 36-year-old Federer is seeking his first US Open title since 2008. With former US Open champions Novak Djokovic (2011, 2015), Stan Wawrinka (2016) and Andy Murray (2012) pulling out owing to injuries, Federer is the strong favourite to add another Grand Slam title to his storied career. The other favourite, Rafael Nadal, also began his campaign with a victory Tuesday against Serbia's Dusan Lajovic.

“I was quite up and down. In these best-of-five-set matches, you have a lot of lives sometimes My hope and my belief is that it’s only going to get better from here,” Federer said, admitting that luck played a part in his victory.

Tiafoe took away many positives from the defeat. “He won by the skin of his teeth. Eventually, I’ll win more than I lose these.”

Roger Federer and Australian tennis sensation Nick Kyrgios are likely to clash during the fourth-round of the ongoing US Open. The 14th-seeded Kyrgios would prove to be a credible threat to Federer, who needed a third set tie-breaker to put away the Aussie during the semi-finals of the Miami Open in April.