Taking on Ferrymead Bays in Christchurch, Caversham came out a convincing winner, rattling in five goals in extra time to win 7-3 after 120 minutes of football.
The match went into extra time after the sides finished the 90 minutes locked at 2-2.
Caversham was staring defeat in the face in regulation time but equalised late to deflate the home support.
In the first period of extra time, a Patrick Fleming screamer put the side up 3-2 only for the home side to come back into the match and equalise again.
But that only lit the fuse for Caversham, which went on the attack and knocked in four straight goals with no reply.
Caversham coach Steve Fleming said it was a scoreline not usually associated with a match that went to extra time, but in the end the superior fitness and finishing of his side shone through.
"They got it back to 3-3 but then we just went bang, bang, bang and it was all over.
"We got it right in the end. I didn't think they were fit as us and they put all their eggs in one basket," Fleming said.
"We had seven or eight chances and buried them all and they didn't.
"We probably didn't deserve to win by that much but scoring goals is what it is all about.
"I'm disappointed we conceded three goals but they were a good side who got among us."
The match was tied up 1-1 at the break and Caversham went behind early in the second half.
Facing a long trip home, Patrick Fleming got his side back into the match five minutes before the end of normal time, with a well-placed shot.
Fleming completed his hat trick as Caversham went crazy and Ferrymead Bays lost its shape.
Tom Jackson grabbed a brace while Deeley bagged two goals, both from the penalty spot.
Caversham made three substitutions midway through the second half to try to get back into the game but that led to some tired bodies near the end of extra time.
The side changed its formation after the substitutions, putting more players upfield, and ultimately it paid dividends.
"I'm disappointed we conceded three goals but it was quite a physical match and they gave us plenty to think about."
Patrick Fleming, playing in behind the Caversham attackers, had an outstanding game, and showed plenty of ability to find space.
Hamish Chang made a big impact when he came on in the second half for Caversham.
Caversham will find out tomorrow which side it draws and where it will play in the semifinals.
Fleming was hoping for a home semifinal after having to travel to Christchurch for the quarterfinal.
Caversham was knocked out in the quarterfinals last year by Three Kings United, of Auckland.
Auckland sides East Coast Bays and Bay Olympic and Wellington team Miramar Rangers are the other semifinalists.
