It was the second of two shock results on the third day of action in Milton Keynes.
Stephen Maguire won the last three frames to beat Mark Selby and reach the quarter-finals of the Masters on Tuesday at the Marshall Arena.
Selby, a three-time former champion, had been one of the pre-tournament favourites this year but couldn’t replicate the kind of form that saw him capture a brace of ranking titles during the first half of the campaign.
In fact, Maguire always had the upper hand after winning the first two frames with breaks of 66 and 57.
Selby twice restored parity – at the mid-session interval and again a short time after when the scores were locked at 3-3.
However, the Scot was the heavier scorer throughout the contest and contributions of 65 and 61 helped him to advance.
Maguire will face Yan Bingtao in the last eight after the Chinese youngster fought back superbly from behind on his Masters debut to deny Neil Robertson in a decider.
Like Selby, recent UK champion Robertson was among the heavily fancied players for glory this week and it looked like the Australian was going to coast to victory when he established a 3-1 advantage with the help of three high-scoring visits.
Yet, the 2012 champion’s game fell apart after throwing away a scrappy and elongated fifth frame which allowed his opponent to rally.
When Robertson stretched his cushion to 5-3 it seemed as though he would weather the storm, but the “Thunder from Down Under” succumbed to the pressure as 20 year-old Yan retrieved the deficit for a famous victory.
On Wednesday, the first round will conclude with the remaining couple of matches taking place.
Ronnie O’Sullivan will begin his bid for a record-extending eighth crown when he meets Ding Junhui in a mouthwatering affair.
Two other former champions go head-to-head later in the day when John Higgins entertains Mark Allen.
Live coverage is being provided by Eurosport and the BBC across Ireland and the UK, with further broadcasts also available around the world.