Four seeded players have been knocked out of the Heineken Open men's tennis tournament in Auckland on day three.
The American Steve Johnson upset fourth seed Kevin Anderson of South Africa in straight sets to book his place in the quarter-finals against Taipei's Yen-Hsun Lu.
Johnson, ranked 160 in the world, earlier upset the former top-10 player, Marcos Baghdatis of Cyprus, in a rain-delayed first-round match.
The sixth seed, France's Benoit Paire was easily beaten by the Spaniard Roberto Bautista-Agut 6-3 6-4.
The second seed Tommy Haas was defeated 6-4 6-4 by the American wildcard Jack Sock, who's ranked 88 places below the 12th-ranked German.
The ninth seed, Germany's Daniel Brands, was eliminated in a rain-delayed first-round match by the American qualifier Bradley Klahn, 7-5 4-6 6-3.
The tournament's fifth seed , Philipp Kohlschreiber, has breezed into the quarter-finals though, defeating the Argentinian Horacio Zeballos 6-4, 6-2.
He will meet the American third seed, John Isner, who needed three sets to beat the Slovakian qualifier, Lukas Lacko.
The former top 10 player, Marcos Baghdatis, went down in three sets earlier on Wednesday, losing to America's Steve Johnson 5-7 7-6 4-6.
The top seed and three-time defending champion, David Ferrer of Spain, made his first appearance against another American, the qualifier Donald Young, the former junior world number one giving Ferrer a scare by winning the first set in a tiebreak.
The American broke Ferrer's serve three times in the first set, and despite the Spanish battler breaking back straight back each time, and Young missing two set points, the 24-year-old left hander finally won the epic opener in a tiebreak, 7-5 in just under an hour.
That only seemed to fire up Ferrer, and the 31-year-old took the second set 6-3 in half the time, then the third 6-1, in just 24 minutes.