Great Britain have struck the first blow in the battle to reach the ATP Cup semi-finals with Dan Evans downing America's John Isner in straight sets.
Evans claimed a 6-4 7-6 (7-3) victory over the world No.24 to give Great Britain the upper hand in Group C, which also features Canada and Germany.
The winner of the tie between Great Britain and the United States will keep their semi-final hopes alive.
The two further rubbers in Thursday's tie pit British No.1 Cameron Norrie against Taylor Fritz before Fritz and Isner face Jamie Murray and Joe Salisbury in the doubles.
Evans has now won all three of his singles matches and has yet to drop a set all week.
After breaking Isner on the American's second service game the Briton never looked back and wrapped up victory courtesy of a tiebreak in the second set.
"It was really important to concentrate early, focus," Evans said.
"We don't really play this early that often, so I got up extra early this morning and really made a conscious effort to come out of the blocks."
Later, Germany meet Canada in Group C's other tie.
German duo Jan Lennard Struff and Alexander Zverev take on Denis Shapovalov and Felix Auger-Aliassime in the singles respectively, before the Canadian pair team up to face Tim Puetz and Kevin Krawietz in the doubles.
