Roger Federer of Switzerland celebrates his win against Frances Tiafoe of the United States during their first-round match at the US Open. Shannon Stapleton / Reuters
Roger Federer of Switzerland celebrates his win against Frances Tiafoe of the United States during their first-round match at the US Open. Shannon Stapleton / Reuters

Roger Federer escapes in five sets to advance at US Open, defending women's champion Angelique Kerber bows out in first round