Cross averaged a staggering 106.99, even hitting two perfect 10-darters early on. Despite needing a last-leg escape in the first round, he looked dominant against Searle, never relinquishing a lead after building a two-leg cushion.
"I still think there’s more in the tank," insisted Cross, despite recording his highest average on the Winter Gardens stage.
"I am enjoying the game. It is not complicated for me at the minute; I'm playing with freedom, and if I carry on, who knows where I can end up?
"I love this tournament. I have always loved this tournament since I walked into this building eight years ago."
Michael Smith had a tougher route, needing to overcome a determined Chris Dobey to win 11-9.
Dobey, who beat Smith in both the World Matchplay and World Championship last year, pushed Smith hard after the early leader went 4-0 up.
Dobey even came close to a match-tying 135 checkout, but Smith held his nerve to advance.
A relieved Smith said he "wasn't at the races" despite the win.
"I was 4-1 up without playing well. Chris gave me a lot of chances early on, and then I got involved in a battle I should never have got involved in.
"It was a bit nervy going into the last three or four legs, but I managed to get over the line and I’m in the quarter-finals now, which is good."
Three-time champion Michael van Gerwen continued his title pursuit with an 11-8 victory over Joe Cullen.
Despite a strong start from Van Gerwen, Cullen threatened a comeback, winning three legs to make it 9-8.
However, Van Gerwen shut the door and will now face Andrew Gilding in a rematch of their epic 2023 UK Open final.
Gilding, meanwhile, made history by reaching his first World Matchplay quarter-final with a convincing 11-5 win over Krzysztof Ratajski.
He built a comfortable lead early with high finishes and held off a late surge from Ratajski to seal the win with a 98 average.
"I cannot wait to play my next game. I'm buzzing," declared Van Gerwen, who faces Andrew Gilding in the last eight.
Thursday’s action at the Betfred World Matchplay will see the first two quarter-finals take place, as World Champion Luke Humphries faces 2020 champion Dimitri Van den Bergh, in a repeat of March’s UK Open showpiece.
The evening's opening last-eight tussle will see 2007 winner James Wade take on former European Champion Ross Smith, who denied 2022 runner-up Gerwyn Price on Tuesday to reach the quarter-finals for the first time.
