Rafael Nadal yesterday pulled out of Spain’s opening ATP Cup tie with a lower back problem less than a week before he bids for a record 21st guys’s Grand Slam title at the Australian Open.

The world second, 34, was set up to face Australia’s Alex de Minaur at Melbourne Park on Tuesday.

Nadal said he intended to play for 2020 runners-up Spain against Greece on Thursday.

Novak Djokovic previously provided protecting champs Serbia a winning start.

World primary Djokovic beat Denis Shapovalov 7-5 7-5 as Serbia declared a 2-1 win over Canada in their opening Group A match.

Milos Raonic had actually put Canada ahead with a 6-3 6-4 win over Dusan Lajovic however Djokovic and Filip Krajinovic won the doubles match versus Raonic and Shapovalov 7-5 7-6 (7-4).

Defending Australian Open champion Djokovic has won all 10 singles and doubles matches he has dipped into the ATP Cup, which was introduced to the tennis calendar in 2020.

United States Open champion Dominic Thiem had a disappointing day as Austria lost 2-1 to Italy.

World number three Thiem, who reached the last of the Australian Open last year, was beaten 6-2 6-4 by 10th-ranked Matteo Berrettini.

Compatriot Denis Novak beat Fabio Fognini 6-3 6-4 however the Italians paired for the doubles match to beat Novak and Thiem 6-1 6-4.

The men’s group event, which has been reduced to 12 groups from 24, is being played at the exact same time as five other tournaments at Melbourne Park this week after a strict quarantine for all players who got here in the nation for the Australian Open.