Auckland opened the scoring 4th minute through front rower Charlie Gubb, who burst through some weak defence to power under the posts. Pita Godinet converted for an early 6-0 lead.
Wests Tigers defended their line from repeated Vulcans pressure and were able to repel multiple sets of six before scoring with their first attacking chance.
Eddy Pettybourne ran a great line to the right of the posts to slice through off a Jack Madden short ball in the 15th minute.
Eddie Paea hit the posts with the conversion attempt to see Wests Tigers trail 6-4.
That was about as long as Pettybourne lasted, limping off with an ankle injury shortly after.
Wests Tigers thought they had another try shortly before halftime, but try scoring freak Taqele Naiyaravoro's cross was ruled out after a forward pass.
Auckland made Wests Tigers pay, replacement Salivi Havila scoring right on half time with Godinet making the score 12-4 going to the break.
Wests Tigers got the best possible start to the second half with a huge Eddie Paea cut out ball evading potential intercept to give winger Allan McGrath a free run to the line.
Paea kicked from the sideline to put Wests Tigers within two points, 12-10.
Wests Tigers were on the attack in the 53rd minute but halfback Jack Madden threw an intercept pass to see Pita Godinet race 90 metres to score. A conversion from under the posts gave Auckland an 18-10 lead.
With a quarter of the game remaining, Wests Tigers had a glut of possession on the line, but lacked spark in attack and looked unlikely to crack the Vulcan's defence.
The game was lacking in intensity until Agnatius Paasi hit a falling Michael Bullock with with a spectacular shoulder charge. The Vulcan was sent from the field, while Bullock was stretchered off.
Wests Tigers fired up and finally crossed the line through giant Naiyaravoro who athletically grounded in the corner.
Paea missed from the sideline leaving Auckland with an 18-14 advantage.
Auckland attempted to slow the game down, but were made to pay by Asipeli Fine who scooted from dummy half and stretched out to score.
Paea crucially missed his third conversion of the day to leave the scores tied up at 18-all with 3 minutes remaining.
A thrilling conclusion ensued, with Wests Tigers making a break down field. A retreating Sam Lousi tapped down a pass from an offside position and was sin binned.
Paea slotted the conversion to give Wests Tigers a thrilling 20-18 win.