Ronnie O'Sullivan suffered a first-round exit at the Masters yesterday as Mark Allen battled to a 6-4 win at Wembley Arena.
Allen had dominated the early exchanges, leading 3-1 at the mid-session interval but O'Sullivan, down at No 9 in the world rankings, fought back to 4-4.
The Northern Ireland player recovered his poise, though, and came through to set up a contest with either Stephen Hendry or the world champion Neil Robertson. Allen told BBC Sport: "There wasn't any quality so much as bottle, I've shown that over the last few years.
"He put me under a lot of pressure from 4-2, his long potting was phenomenal, but if somebody had given me 4-4 at the start I would have taken it – it's best of three from there and I'm capable of beating Ronnie. He wasn't at his best but I'm happy to win."
O'Sullivan added: "It was a tough match, all credit to Mark. He's had a great season, got to the semi-finals of the UK and the World [Championship] and he's a big-time player. I had great support but you've got to do the business on the table."