PARIS (AP)—Novak Djokovic’s match against Juan Martin del Potro in the French Open’s third round was suspended because of darkness Friday night with the players tied at a set apiece.

Djokovic won the first set 6-3, and del Potro took the second 6-3. As they went to the sideline, the chair umpire announced play would stop for the day.

Two-time Australian Open champion Djokovic is 39-0 in 2011 and has a 41-match winning streak dating to December. Del Potro won the 2009 U.S. Open and was a semifinalist at Roland Garros that year.

They played for 1 hour, 37 minutes before Friday’s match was halted at 9:15 p.m.