Mark Allen crashed out at the first hurdle in the defence of his Dafabet Masters title after losing to Luca Brecel in a final-frame decider at Alexandra Palace.
The Northern Irishman made a significant career breakthrough a year ago when he beat Kyren Wilson 10-7 in the final to claim his first Triple Crown trophy.
However, his bid for a repeat showing this year was over almost before it had begun as Brecel avenged his 6-3 defeat to Allen on his Masters debut in last year's first round.
Brecel racked up four half-century breaks and a superb 140 to dispatch the defending champion in what was an entertaining start to the 2019 tournament.
The 23-year-old started with a composed break of 75 before Allen hit back with a run of 67, only for Brecel to hit 50 in the next to lead 2-1.
The Belgian took the fourth frame – the only one not to feature a half-century break – to extend his lead to 3-1, but 32-year-old Allen restored parity with breaks of 96 and 136.
However, Brecel went one better with a brilliant 140 to move 4-3 ahead before the duo traded the next three with runs of 83, 88 and 99 to force a deciding 11th frame.
But Brecel held his nerve to knock in his fourth half-century to send Allen home early and set up a second-round clash with the winner between Ding Junhui and Jack Lisowski.
In the evening session, there was another final-frame thriller as Ryan Day dumped out two-time Masters champion John Higgins in their first-round clash.
Higgins edged a tense first frame when he cleared up – winning on the black – before racking up a 65 break to take a 2-0 lead.
The pair traded the next two frames as Higgins earned a 3-1 mid-session interval advantage, however Day stormed back with three successive breaks of 52, 111 and 83 to lead for the first time.
The Scotsman hit back to level at 4-4 but Day sunk a superb long pink and equally difficult black when 48-47 down to clinch the ninth frame, only for Higgins to force a decider.
However, Welshman Day held his nerve with a terrific match-high break of 128 to claim victory and set up a second-round match with Ronnie O'Sullivan or Stuart Bingham.