In a match of stark momentum swings, Wilson lost seven frames in a row in the course of becoming the 20th first-time Crucible champion to fail to defend his title.
No first-time winner has been able to retain the world crown since the tournament moved to Sheffield’s Crucible Theatre in 1977.
Lei, one of a record 10 Chinese players in this year’s draw, looked down and out when trailing 6-2.
But he staged a stunning recovery, including a run of six consecutive half-century breaks, to move to the brink of victory on Saturday’s opening night of the championship.
The 21-year-old then had to withstand a Wilson comeback before delivering a break of 66 under intense pressure in the decider to send the defending champion tumbling out.
“Obviously it’s really hard to take,” said 33-year-old Wilson. “I’ve got such a strong record at the Crucible and I was nowhere near my best but it still took a 10-9 to beat me.
“It’s been a really long season and I’ve done so much. I’ve never been stretched so much in all my life but I’m proud of the way I’ve handled it and I’m proud of the success I’ve had as well.”
Wilson, who has won four ranking titles this season, had expressed confidence that he would be the man to put the 48-year-old curse to bed.
He was in total control against Lei when he led 6-2 but the Scottish Open champion roared back to lead 9-6.
“It feels amazing,” said Lei. “The Scottish Open was my first title and this was my Crucible debut, both moments are very special to me. The emotions were just as intense.”
The world number 39, who had to come through qualifying, will face Zhao Xintong or Jak Jones in the last 16. (AFP)
