Zverev hits back for Germany after Kerber loses heavily at United Cup

German star Alexander Zverev overpowered Greek world number six Stefanos Tsitsipas 6-4 6-4 on Friday to leave the nations' quarter-final clash at the United Cup evenly poised.

Earier Germany's Angelique Kerber suffered the first big defeat of her return to tennis, going down 0-6, 3-6 to Greece's Maria Sakkari in Sydney.

The former world number one is making her comeback from having a baby but 18 months away meant she was no match for the Greek, who won in 1 hour 14 minutes with her third match point.

The two singles matches mean the tie in the mixed-team tournament is now at 1-1, with the mixed doubles to decide the semi-finalist on Saturday.

Kerber had previously lost to Italy's Jasmine Paolini and France's Caroline Garcia at the tournament but the Sakkari defeat was the first time she has been outclassed.

Germany had beaten Italy and lost to France in the preliminary round. The team competition is regarded as preparation for the Australian Open in Melbourne, which begins on January 14.