Jan 1 (Reuters) - World number four Stefanos Tsitsipas pulled out of his ATP Cup singles match with Poland"s Hubert Hurkacz on Saturday due to a niggling right elbow issue before returning to partner Michail Pervolarakis to win their doubles rubber. Tsitsipas and Pervolarakis defeated Hurkacz and Jan Zielinski 6-4 5-7 10-8 in the doubles match but Greece suffered a 2-1 loss to Poland after losing both their singles match. Aristotelis Thanos, who replaced Tsitsipas in the singles tie, lost 6-1 6-2 to Hurkacz, while Kamil Majchrzak defeated Pervolarakis 6-1 6-4 in the second singles match. Tsitsipas, who had posted pictures of himself on a hospital bed during the off-season following surgery, said he decided to take it "a bit easier" by starting with the doubles match. "I"m truly relieved that I"m able to feel normal again after years and years of suffering. The concern was kind of something that I expected, but it"s not serious. I"m just trying to protect it," the 23-year-old said. "I"ve been using some muscles that I haven"t been able to use before and it takes a little bit of time to get into the rhythm and get to the level I want to. "If I"m not able to perform at 100 per cent, for me there"s no reason for me to go out there and play." Tsitsipas was forced to retire from the second round of the Paris Masters and lost his opening match against Andrey Rublev at the ATP Finals in November before withdrawing from the season-ending tournament due to the elbow injury. He had earlier played down concerns that the injury would derail his campaign at the Australian Open, which begins on Jan. 17 saying his withdrawal was a "precautionary step" to ensure he remains fit for the Grand Slam.