In the end the pressure got to Otago and City completed their task with three unanswered second half goals through Emiliano Tade, Stephen Carmichael and veteran Daniel Koprivcic.
It was a brave effort by the visitors in difficult conditions. Neither goalkeeper Liam Little (Auckland) and Peter Evans had much to keep them warm in the first half but Evans was busier in the second.
Four minutes after Angel Berlanga had a header hooked off the line, City went ahead through Tade who gave the hosts their 69th minute lead. The rest of the scoring came in time added on.
Andrew Milne, on for Luis Corrales, set up substitute Carmichael for the second goal, scored in the second added minute.
Two minutes later Koprivcic sealed the deal.
It was a weekend to forget for defending champions Waitakere whose youth team also suffered defeat, going down 2-1 to Canterbury United in Saturday's defence of the ASB Youth League title, despite taking an early lead.
The senior team's flight south to Christchurch yesterday was delayed by heavy rain which rushed their arrival and put the kick-off time back.
Waitakere dominated for long periods but fell a goal behind to a Cole Peverley penalty on the half hour and went 2-0 down in the 85th minute when substitute Calvin Opperman scored.
Gagame Feni's strike in stoppage time was a mere consolation.
Coach Neil Emblen was left to puzzle over his team's inability to convert the half dozen or so clear scoring chances his players had created.
The league takes a break until mid-January when Auckland host Canterbury in the match of the round.