1991 U.S. Pro Indoor

The 1991 U.S. Pro Indoor was a men's tennis tournament played on indoor carpet courts that was part of the Championship Series of the 1991 ATP Tour. It was the 24th edition of the tournament and was played at the Wachovia Spectrum in Philadelphia, Pennsylvania in the United States from February 11 to February 18, 1991. First-seeded Ivan Lendl won the singles title, his second at the event after 1986.

1991 U.S. Pro Indoor

The 1991 U.S. Pro Indoor was a men's tennis tournament played on indoor carpet courts that was part of the Championship Series of the 1991 ATP Tour. It was the 24th edition of the tournament and was played at the Wachovia Spectrum in Philadelphia, Pennsylvania in the United States from February 11 to February 18, 1991. First-seeded Ivan Lendl won the singles title, his second at the event after 1986.