Nevertheless, it would be a heartless man to deny that Napier were impressive on a bumpy pitch and it's clear that they will be contenders for the cup this season, whatever the rest of the country throws up.
"It's a positive day for us. It was a difficult pitch and it was played in tricky conditions being very windy, and they made things very difficult for us in periods, but overall I'm happy with the performance," said Robertson.
"We should have scored a few more goals; had we taken our chances we could have killed them off a lot earlier."
The visitors certainly began with the bit between their teeth, taking the lead with just three minutes gone, Greatholder side-footing the ball into the net. After Tawa's Mike Ramaekers got one back, Welshman John won a priceless free-kick when he was tripped up by a home defender, and Bevin hit the ball over the wall and into the far corner. Five minutes before the end of the half, Robertson nodded the ball goalwards for John to stroke in from close range.
On 62 minutes, Tawa's Andrew Wild handled the ball in the box though it seemed as if he knew little about it, and Kilkolly easily slammed the ball home from the penalty for a 4-1 lead.
Thereafter, Napier attacked relentlessly but without reward. Bevin was deprived by goalkeeper Lance Ramaekers, Josh Stevenson sliced the ball wide, Liam Messam should have been more accurate and Ryan Tinsley struck the post. Kilkolly was denied by a defender putting his body on the line then soon after hit the post.
Robertson, after missing the rebound from Tinsley's effort, tore back into defence and bravely threw himself at a Tawa shot to prevent an almost certain goal. With less than a minute to go Russell Kyne's cross benefited from the wind to sail past Jonty Underhill.
In the Central region's other cup last-16 match, Island Bay United of the Capital Premier League created a major shock by beating runaway Lotto Central League leaders Miramar Rangers 3-2 on Saturday.
In Central League action, Olympic beat Petone 1-0, Palmerston North Marist beat Wairarapa Utd 3-2 away and Upper Hutt City beat Lower Hutt City 4-3 at home.