The sky is the limit for Si Jiahui, who continued his giant-killing act by upsetting Anthony McGill 13-12 in a thrilling World Snooker Championship quarterfinal. 

The 20-year-old Chinese debutant, who is the lowest-ranked player left in the tournament at 80th, fought back from a slow start and held his nerve in the final-frame decider to complete a shock win over the Scottish veteran. 

Having won three qualifying matches to reach his first ever World Championship, Si stunned former world champion Shaun Murphy and Welsh Open winner Robert Milkins before knocking out McGill in an incredible run. 

Si's triumph on Wednesday night meant that he has now become the youngest World Championship semifinalist in 27 years and the first debutant to reach the last four in 28 years. 

"I feel very lucky because there were times I didn't think I could win," said Si, who is also only the third player from the Chinese mainland to have reached the semifinals of the event. "I kept it tight and kept my nerves under control. I just wanted to concentrate to perform under this extreme pressure. My mindset changed but I held myself together very well. 

"All the spectators were watching. I was offered a lot of opportunities during the match by my opponent, and I thought with that many chances I wanted to win. I felt the desire, which was different from previous matches.  

"I've learned something from this experience and I will be playing under a better mindset from now on. I used to tremble because of nerves in deciding frames but I'm able to get through it more consistently, mentally stronger."

After suffering an early exit last week, Murphy predicted that Si would become the first World Champion from China, but the Chinese wunderkind insisted there is no need to get carried away by the emotion of the occasion. 

"I will keep trying my best, but I don't want fans to expect too much," he observed. "I am surprised to get this far because I didn't think I was at the level of players who can make it to the semi-finals. I need to improve." 

Next up for Si is a semifinal encounter with Luca Brecel, who ended Ronnie O'Sullivan's hopes of an eighth World Championship title with a dramatic 13-10 comeback victory earlier in the day.