NEW YORK (AP) -- John Isner is not the sort to study a lot of video of past matches in order to prepare for an upcoming opponent.
If the highest-ranked American man wanted to, he'd have plenty of material in order to prepare for the task he faces Saturday: facing 22nd-seeded Philipp Kohlschreiber of Germany in the third round of the U.S. Open.
This is, after all, the third consecutive year that Isner will meet Kohlschreiber in the third round at Flushing Meadows.
''I'm not a big game-tape guy myself, but my coach - I know he watches that and then he relays it to me,'' said the 13th-seeded Isner, who is 31 for 31 in service-game holds this week. ''But certainly ... it's a weird situation. We have played three years in a row in the third round at this event. It's bizarre.''
Kohlschreiber is 2-0 in those New York matchups, winning in five sets in 2012, and in four a year ago.
Isner, though, has won all four of their other matches against each other.
Here are some other things to watch on Day 6 at the year's last Grand Slam tennis tournament:
DJOKOVIC VS. QUERREY: Isner is one of two American men left in the field. The other is Sam Querrey, a former top-20 player now ranked 57th who has the unenviable task of facing No. 1-ranked and No. 1-seeded Novak Djokovic.
They've played each other eight times previously, and Djokovic has won seven of those.
Djokovic is also 7-0 in U.S. Open matches against American opponents. The seven-time major champion is seeking to get to the fourth round in New York for the eighth year in a row.
SERENA VS. AN AMERICAN: For the third time in three matches at this year's U.S. Open, Serena Williams faces an American, this time 52nd-ranked Varvara Lepchenko.
Williams has won 16 matches in a row at Flushing Meadows; she can become the first woman with three straight titles at the tournament since Chris Evert took four in a row from 1975-78.
There's still plenty of work to go, but if Williams can grab the trophy, it would give her 18 Grand Slam singles championships, equaling the total achieved by Evert and Martina Navratilova.
Williams earned her 17th at the 2013 U.S. Open, then lost in the fourth round at the Australian Open, the second round at the French Open, and the third round at Wimbledon.
''I've had three tries to get to 18, and it hasn't happened. ... Hopefully I'll get there one day,'' Williams said. ''I'm kind of stuck right now at 17, which to be honest is not a bad number to be stuck at. It's better than 16.''
KYRGIOS UNDER THE LIGHTS: One of the sport's new faces is 19-year-old Nick Kyrgios, a lanky Australian with a big serve who stunned Rafael Nadal in the fourth round at Wimbledon.
Kyrgios also is something of a volatile sort, earning enough code violations from the chair umpire in his first-round victory Monday that he came within one outburst of being disqualified.
His third-round opponent Saturday night in Arthur Ashe Stadium will be 16th-seeded Tommy Robredo of Spain.
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