German newspaper Bild reported earlier this week that Ozil, formerly of Real Madrid, partied with the likes of Neymar, Dani Alves and Gerard Pique until 7am Sunday morning alongside his fellow Germany international Julian Draxler.
But Xavi said he saw no sign of the Arsenal playmaker, who played the full 90 minutes in Germany's 2-1 defeat to the United States on Wednesday night.
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"I did not see [him]," Xavi was quoted as saying by Spanish newspaper Sport. "I was with family and my friends. At three I went to sleep."
Xavi may have been telling the truth - or perhaps he turned a blind eye, keen not to grass up the 26-year-old.
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Ozil criticised for nightclub appearance in March
Ozil was criticised earlier this year after being spotted at a Berlin nightclub, hours after pulling out of Arsenal's 2-1 win over Newcastle United due to illness.
Some Arsenal supporters were understandably perturbed by the reports - particularly because Ozil had failed to set the Emirates Stadium alight following his big-money move from Real Madrid in the summer of 2013 - but Arsene Wenger opted against disciplining the technically-gifted midfielder.
"He went out for half an hour to a birthday for his friend to wish him well," the Arsenal manager was quoted as saying by ITV Sport. "You can't stop someone wishing happy birthday to a friend!"
Arsenal fans still waiting to see the real Ozil
It was a lenient approach from Wenger - but Ozil repaid his manager's confidence with some superb performances in the final months of the season.
Arsenal fans are still yet to see the very best of Ozil, who was arguably the best No. 10 on the planet during his three-year spell with Real Madrid.
Big things were expected of the playmaker whose lackadaisical demeanour can often be mistaken for a lack of effort, but he has failed to scale the heights many expected he would after completing his £42.4 million move from the Bernabeu.
Wenger has consistently defended Ozil, who will be under pressure to perform well on a more consistent basis next season.
A summer off should certainly help - Ozil believes this season has been the toughest of his career - leaving him revitalised ahead of the 2015-16 campaign.
Arsenal fans: have you been happy with Mesut Ozil's performances since he arrived at the Emirates Stadium? Have your say in the comments below!