By Amy Tennery
NEW YORK (Reuters) - John Isner ground out yet another three-hour-plus match at the U.S. Open on Sunday, nailing critical break points to beat Canadian Milos Raonic a 3-6 6-3 6-4 3-6 6-2 and advance to the quarter-finals of his home Grand Slam for the second time.
The American fired 56 winners and 20 aces to down the former world number three in front of a rowdy and elated crowd of his compatriots inside the newly-built Louis Armstrong Stadium.
Isner endured a five-set bout in the second round of the tournament and a three hour and 26-minute blockbuster in the third, but the eleventh seed showed few signs of fatigue.
"This crowd kept me in it – it was fantastic," Isner said in an on-court interview after the three hour and eight-minute match. "This is why us tennis players train so hard ... to be in a match like this in front of a crowd like this."
Isner next meets either Croatian Borna Coric or third seed Juan Martin del Potro, who play their fourth round match later on Sunday in Arthur Ashe Stadium.
(Reporting By Amy Tennery, editing by Nick Mulveney)