Ronnie O'Sullivan's Saudi Arabia Masters campaign came to an end in the quarter-finals after a 6-4 defeat to Si Jiahui.
A break of 87 in the second frame allowed Jiahui to open up a 2-0 advantage but breaks of 65 and 79 enabled O'Sullivan to level the match.
But Jiahul responded and a 50 break saw him move back ahead before a run of 96 moved him within one frame of victory as he took a 5-2 lead.
O'Sullivan rallied with breaks of 65 and 56 to reduce the lead to 5-4 but Jiahui held his nerve to close out the match with a break of 82.
"Overall I think I played really well in this match," Jiahui said on the World Snooker Tour website.
"I tried to relax myself and avoid getting too nervous about the occasion. I am pleased with how I dealt with getting over the line in such a big game.
"This is a very big tournament and there are a lot of ranking points attached.
"I am trying as hard as I can not to think about this. It allows me to play as well as I can. I just concentrate on my own game and that is where that performance came from."
Judd Trump claimed a place in the last four with a 6-3 victory over Neil Robertson.
The world number one started strongly and a break of 100 moved him into a 3-0 early lead.
Robertson fought back and a break of 77 reduced it to 3-2. A run of 67 put Trump 4-2 up but Robertson's 101 saw the deficit reduced to one once more.
But Trump took the next two frames to advance to the semi-finals.
Trump said: "Neil was looking a lot more confident than he has done recently, it was just the odd little mistake when it really mattered. I know against someone like him if he got level he would have started peacock-ing round the table.
"It is never nice when your opponent has the momentum, but I just managed to stay in front."
Shaun Murphy will face Trump in the last four after be beat Xiao Guodong 6-2, while world number nine Mark Williams completed the semi-final line-up with a 6-0 whitewash of Jimmy Robertson.
