The win propels Wade into the quarter-finals alongside Luke Humphries, Dimitri Van den Bergh, and Ross Smith.
Aspinall, playing through the pain of a persistent arm injury, fought valiantly but couldn’t overcome Wade’s determination.
The latter stormed to a 4-0 lead before Aspinall clawed his way back to lead 8-7. However, Wade demonstrated his experience and composure, winning the final four legs to seal the match.
"Nathan didn't play how he can so I'm a lucky boy tonight," said Wade, a former winner in 2007, after the victory.
"But the main thing is I'm through and I'm happy to still be in the tournament.
"I've got nothing to prove; no one has won as many tournaments as me apart from Michael (Van Gerwen) and Phil (Taylor)."
Wade will face Ross Smith in the next round after Smith produced a stunning 11-9 upset over Gerwyn Price.
Both players struggled early on, but Smith found his rhythm in the latter stages to secure a maiden World Matchplay quarter-final spot.
World number one Luke Humphries continued his impressive campaign with an 11-7 win over Stephen Bunting. Humphries averaged a remarkable 102.34 but faced a stern test from Bunting before pulling away in the closing stages.
"I didn't have it all my own way," said reigning world champion Humphries, a semi-finalist last year.
"Stephen is a battler and he put me under pressure in every leg.
"He's a lovely man and I can see why he gets so much support.
"It was a fantastic game of darts, it always is when we play each other.
"I know I can win it, I've won the biggest tournament in the world, it's not going to be easy but I'm ready to fight for this title."
Van den Bergh completed the quarter-final line-up with a 11-5 victory over Jonny Clayton, avenging last year’s defeat.
The Belgian produced a crucial 112 checkout to take control of the match and seal his place in the last eight.
The World Matchplay continues on Wednesday with high-profile clashes including Michael van Gerwen against Joe Cullen and Rob Cross facing Ryan Searle.
