A blockbuster ASB Classic semi-final between Caroline Wozniacki and Agnieszka Radwanska is one step closer to reality after the Polish world No.28 outclassed second-round opponent Taylor Townsend 6-3 7-5.

Radwanska coasted through her first set in Wednesday night's Auckland action but struggled in the second, requiring a late break to emerge victorious.

The ex-Wimbledon finalist raced to a 4-1 first-set lead before the heavens opened, halting her march to victory and partially breaking her stride.

READ MORE: Wozniacki demolishes competition at Classic

The 28-year-old duly played out the set before going toe-to-toe with Townsend in the second and ultimately winning the decisive break at 5-5.

She'll go into Thursday's quarter-final against Sachia Vickery - should rain hold off - a firm favourite, as she seeks to repeat her 2013 title-winning heroics.

But to do so, she's almost certainly going to have to go through the world No.3 Wozniacki, who obliterated Petra Martic 6-2 6-2 earlier in the day.

The 27-year-old Wozniacki and Radwanska are on the same side of the draw, with Wozniacki to play her quarter-final against American Sofia Kenin.

Fresh off Tuesday night's straight-sets demolition of Madison Brengle, the Danish top seed again breezed past her opponent, winning within an hour.

At times, Wozniacki's groundstroke play was stunning.

She repeatedly pulled winning shots out of the bag as she broke twice to secure the first set and then went on a six-game run to round out the result.

"A couple mistakes here and there but, all in all, I can be pretty happy with my performance - especially because she's an aggressive player and serves big, but I managed to serve well and get a lot of returns in," Wozniacki said.

"I'm building on my game all the time - I still have a little time before Melbourne (the Australian Open) so hopefully I can get some more matches here."

German second seed Julia Goerges is also in the hunt.

The world No.14 was similarly destructive against Slovakian teen Viktoria Kuzmova, winning 6-4 6-0 and playing her opponent off the court in 65 minutes.

She has a slightly easier run to the final, with only Czech Barbora Strycova - who beat Johanna Larsson on Wednesday - appearing genuine opposition.

Goerges will play Polona Hercog in her quarter final, while combustible third seed Strycova will take on Taiwanese player Su-Wei Hsieh.

"I felt much more calm than I did in the first round and it's just the way you get used to the match conditions again after a long break," Goerges said.

Rain and strong winds are forecast to batter Auckland for Thursday and much of Friday, possibly complicating the work of Classic organisers.

Schedules could be heavily delayed by Friday's play.