Zverev, Tsitsipas upset at ATP Cup

Sydney : Alexander Zverev and Stefanos Tsitsipas both crashed to defeat in their first matches of the year Friday as day one of the inaugural ATP Cup sprung some big upsets.

The German world number seven was stunned by Australia's fast-improving Alex de Minaur, who rallied from a set and 4-2 down to win 4-6 7-6 (7/3) 6-2.

Greek star Tsitsipas, who won the 2019 season-ending ATP Finals in London and is now ranked six, slumped to a 7-6 (8-6) 7-6 (7/4) loss to young Canadian Denis Shapovalov.

It led to both Germany and Greece being defeated in their opening ties at the 24-nation event, where the countries are split into six groups across Sydney, Brisbane and Perth.

The top eight from the round robin go onto the knockout phase in Sydney before one is eventually crowned the winner.

Along with Australia and Canada, Belgium also won, sweeping Moldova 3-0, while tennis minnows Norway pulled off a big 2-1 upset against the United States.

Drawcards Rafael Nadal and Novak Djokovic make their debut on Saturday, for Spain in Perth and Serbia in Brisbane respectively.

"It's definitely up there," said de Minaur in Brisbane, when asked how the victory ranked in his career. "This one feels very, very good.

"I have a great team. My captain, my coach were all making sure I stayed in the moment and told me I would have chances."

Earlier, Nick Kyrgios beat Jan-Lennard Struff 6-4 7-6 (7/4). "First game, first match of the year is always going to be tough," said Kyrgios, who has pledged AUD 200 for every ace he serves during the Australian tennis summer to help victims of bushfires that are raging across Australia.

Tsitsipas went into his match with Shapovalov, also in Brisbane, as slight favourite, with the Canadian ranked nine places below him. But Shapovalov's left-handed serve was working beautifully and Tsitsipas faltered at key moments in both tiebreaks.

"His serve was better than mine and a few points in the tiebreak, I didn't work out what I had to do and I didn't have a clear picture of how I have to play," said the Greek.

With teammate Michail Pervolarakis being thrashed by Felix Auger-Aliassime in two quick sets, Greece lost their opening tie.

The United States were also upset, with emerging Norwegian youngster Casper Ruud beating big-serving John Isner. He then backed up in the decisive doubles alongside Viktor Durasovic to ensure the win.

Earlier, Taylor Fritz had thrashed Durasovic 6-2 6-2 to give the US a 1-0 lead. The ATP Cup, from January 3-12, features two ties each day in the three cities during the round robin, comprising two singles matches then a doubles.