Juan Martin Del Potro continued his promising return from an 11 months injury layoff by beating top seed Fabio Fognini 4-6, 6-2, 6-2 on Wednesday to reach the quarterfinals of the Sydney International.

The second-round triumph over Fognini further demonstrated his return to top form ahead of next week's Australian Open.

The former No. 4 needed a wildcard to gain entry to the main draw as his world ranking had decayed to 338 during his lengthy absence. He showed the benefit of concerted preparation by beating Fognini in 1 hour, 48 minutes.

Second seed David Goffin of Belgium also suffered a second round loss, going down 6-3, 6-3 to Italy's Simone Bolelli.