Argentinian tennis star Juan Martin del Potro has coasted into the Auckland Classic quarter-finals with a straight-sets win over Canadian Denis Shapovalov.
In what proved a sterner test than his first-up victory against equally youthful Denis Shapovalov, del Potro on Thursday dominated all of the key moments to win 7-6 (7-4) 6-3.
Del Potro, who sealed the Auckland title in 2009, shone in the key moments and fought off six of the seven break points Ferrer forged in a tense clash, with two games in the second set lasting nearly 10 minutes apiece.
The 29-year-old del Potro, an ex-US Open champion and the 2009 Classic victor, will face another ex-champion in Ferrer.
Ferrer, who has won the tournament four times, broke his opponents serve five times (twice in the first set and three times in the second) and was always in control.
"I tried to play consistent and aggressive because with Chung, he plays with power, and it's never easy", Ferrer said in a court-side interview.
Barty downs Gavrilova to reach final By
Barty looked down and out after Daria Gavrilova took the first set 6-3 comfortably, but rebounded to win the next two 6-4 6-2. Barty was gracious in defeat during the presentation ceremony, saying: "It's wonderful to see Angie back playing at her best.
"Unfortunately the match can not have two winners and I'm so happy I won", said the relieved Spaniard, who sank to his knees at the end.
The oft-injured world No.12 will go on to face Bautista Agut, who did it the hard way against semi-final foe Robin Haase by winning 6-7 (7-9) 7-6 (7-3) 7-6 (7-5).
The Australian Open, the first grand slam of the year, runs from January 15-28.
Bautista Agut cruised into Friday's semi-finals with a 7-6 (7-1) 6-2 win over Czech Jiri Vesely, while Haase trumped giant-killing German Peter Gojowczyk.
Having seen the 21-year-old Chung chase down everything Isner fired across the net in the second round, Ferrer was in no mood for long rallies and his plan to look for early winners paid off as he wrapped up the match in 74 minutes.