Former finalist Stefanos Tsitsipas has been knocked out of the National Bank Open in Montreal, falling to Brazilian teenager Joao Fonseca in the second round.
Fonseca defeated the Greek No.1 7-6(3), 7-5 on Wednesday to reach the third round of the ATP Masters 1000 event, extending his winning record against Tsitsipas to 2-0.
The 19-year-old was playing his first tour-level match since Wimbledon, where he lost in the third round to Roman Safiullin. He looked set to close out the match comfortably after taking a 5-4 lead in the second set, but dropped serve while serving for the victory.
Fonseca responded by winning eight of the next nine points to seal the win and become the first Brazilian to reach the third round in Montreal since Gustavo Kuerten.
Tsitsipas, who reached the Montreal final in 2018, has been rebuilding his season after a difficult run of form. The 27-year-old claimed his first title in 16 months at Gstaad last month and had climbed six places to No.47 in the live ATP rankings before the tournament.
The defeat comes as Tsitsipas continues his return towards the upper levels of the sport after previously reaching No.3 in the world.