Juan Martin del Potro has admitted that he is desperately struggling to focus on tennis after having his bag stolen on Saturday.

The Argentine, who came from a set down to beat Richard Gasquet in the opening ATP World Tour Finals Group B match on Monday, had his personal possessions robbed at the weekend as he was awaiting his Eurostar journey to London from Gare du Nord station in Paris.

"It is tough to enjoy the fantastic tournament after my really bad Saturday," Del Potro told the media. "I like to play tennis and I enjoy my work a lot, but someone took some part of my life. It's tough not to think about that.

"One of my things was the rosary. But I had a few things, which mean a lot in my life. I don't have them anymore. I hope to see Pope again. I will never recover this rosary, but a meeting with Pope will be an honour."

Del Potro finished as the tournament runner-up at The O2 four years ago.