World number 24 Janowicz could not contain his excitement after his win over eighth-ranked Tsonga, ripping off his shirt to celebrate as he clinched the match.
"I was really happy especially because I didn't get off to a good start to the season and I was sick," said the 22-year-old Pole. "So this was really important for me."
Del Potro, who won his second round tie on Tuesday, met Pope Francis, a fellow Argentine, after attending mass at the Vatican.
"It was an incredible experience with Pope Francis, something that I'll never forget," said Del Potro.
"It was a dream come true for a guy like me. It was an unforgettable moment. I was very nervous before meeting him, to be able to congratulate him and talk with him. He was nice. Everybody knows he is very humble. Today was a day that I'll remember for ever."