Adelaide, Jan 11 : The No.10 seed Danielle Collins of America edged Switzerland's Jil Teichmann to reach the quarterfinals of the Adelaide International 2. Belinda Bencic, Beatriz Haddad Maia and Petra Kvitova also advanced to the last eight. Collins took seven match points to defeat Swiss qualifier Jil Teichmann 6-3, 7-6(2) on Wednesday to seal a berth in the final eight, her second WTA Tour singles quarterfinal since last March. Collins never lost serve in the first set against Teichmann, though she saved two break points in the eighth game. But she came from 3-1 down in the second set and won four straight games to put herself on the verge of victory. She failed to serve out the win, which set the stage for the contest's most dramatic game. From 0-40 down, Teichmann saved five match points on her serve to tie the second set at 5-5, after six deuces. The American later won six of the first seven points of the tiebreak to wrap up victory. In other action, No.8 seed Bencic of Switzerland registered a straight-set 6-3, 6-3 win over qualifier Anna Kalinskaya, while No.11 seed Brazil's Maia beat American Amanda Anisimova, 6-4, 7-5, to reach the last eight. While Bencic improved her head-to-head record against Kalinskaya to 3-0 with her victory, Haddad Maia broke a winless spell against Anisimova to reach the next round. Two-time Wimbledon champion Kvitova of Czech progressed to the quarterfinals after her Chinese opponent Zheng Qinwen retired mid-way. Coming from 5-3 down in a 71-minute opening set, and saving three set points in the ensuing tiebreak to win it 8-6, Kvitova moved through when Zheng retired due to a left thigh injury. /IANS