LONDON — Playing with his left knee heavily taped following a scary fall in the previous round, Juan Martin del Potro didn't let it slow him down as he beat Andreas Seppi 6-4, 7-6 (2), 6-3 to reach the Wimbledon quarterfinals Monday.

Del Potro twisted his left ankle and hyper-extended his knee during the third set of his win over Grega Zemlja on Saturday, and said he has been icing the knee constantly since.

He said "it's really painful," but that "the doctors are helping me" stay fit enough to play.

The eighth-seeded Argentine converted only two of his 11 break points and needed four match points to close out Seppi, saying he got a bit nervous toward the end.

He will face fourth-seeded David Ferrer in the quarters.

Seppi became the fourth Italian player to lose Monday.