Luke ‘The Nuke’ claimed three wins from three in the group stage to set up a second-round clash against Mike De Decker in Wolverhampton.
Littler has emerged as the tournament favourite after a flurry of high-profile exits, including reigning champion Luke Humphries, Michael van Gerwen and Michael Smith.
Three-time Grand Slam of Darts quarter-finalist Webster believes Littler’s last-16 clash with De Decker represents the final chance to halt the teenage sensation before he builds insurmountable momentum.
“I wasn’t concerned about Littler coming into the tournament, he’s had a few setbacks, but he’s been brilliant this year,” he told reporters. “He breezed through the group.
“I stand by what I said about Littler and Humphries. If you’re going to get them out, you’ve got to get them early.
“If you don’t get Luke Littler in this round, I don’t think you do, and I think he goes on to win the event.”