Tatsuma Ito and Michal Przysiezny claimed the biggest wins of their careers at the Japan Open when the local wildcard knocked out top-seed Stan Wawrinka and the Polish qualifier saved match points to beat Jo-Wilfried Tsonga.
World number 103 Ito sealed the stunning 7-5, 6-2 first-round victory on his second match point, cushioning a backhand volley into an open court after his wide serve had forced Wawrinka out of position.
Australian Open winner Wawrinka struggled throughout the contest at the ATP 500 event, dropping serve four times and hitting 25 unforced errors in his first tour event since losing to Ito's compatriot Kei Nishikori at the US Open this month.
The loss delays Wawrinka's bid to qualify for the season-ending ATP World Tour Finals in London, which the Swiss could have achieved had he reached the final in Tokyo.
He is fourth in the race for one of the eight spots available at the November event.
Meanwhile, Tsonga looked like retiring when he called for the trainer because of a issue with his right wrist when trailing 3-0 in the deciding set against his 142nd-ranked Polish opponent.
The break did the 2009 champion good, though, as he clawed back the deficit and forced a tiebreak but the Frenchman wasted three match points as 30-year-old Przysiezny hung tough to record a 4-6, 7-5, 7-6 upset win at the Ariake Coliseum.
The loss left Tsonga, 12th in the race to London, facing a tough ask to qualify for the ATP World Tour Finals after he followed seventh-placed David Ferrer, who lost in three sets on Monday, in making a first-round exit in Japan.