Without his 81, New Zealand would probably have lost a game it should have comfortably wrapped up.
Having restricted Sri Lanka to 218 for nine, New Zealand made a hash of it through the middle stages until Anderson got it to the point of victory, which was achieved with seven overs to spare.
From an early stage, it was apparent Sri Lanka needed 10 wickets to win. It was never in a position to countenance strangling New Zealand after Brendon McCullum pasted the visiting side on his way to equalling his own record for the fastest ODI 50 by a New Zealand batsman, of 19 balls.
Allrounder Anderson had not reached 25 in his past six innings, so he was due.
His methods are invariably assertive and although he lived dangerously at times - at 15 and 62 he could have been caught at slip, but both would have been screamers - his approach was spot on.
''We thought 219 was a pretty good target,'' Anderson said.
''But the wicket held a lot. It had a tennis ball bounce and it was difficult to get your timing.
''It's a strange wicket. It still does have carry but does hold and when you start getting wickets that do that, or stay low, that's when you start playing into sub-continental hands.''
And therein lies a small concern for New Zealand.
The word is likely to go back to Hagley Oval ground officials: more pace please, before the World Cup opener against the same opponent on February 14.
In the same way New Zealand would have been in a large hole but for Anderson, Sri Lanka relied on veteran Mahela Jayawardene's 18th ODI ton for a workable total.
''He showed the tempo you needed to play on that wicket. It was a brilliant effort,'' Anderson said.
New Zealand was never in danger of a twitchy chase, after McCullum's early assault. It simply had to make sure it got the runs, without having to fret over ball versus runs equations.
In the field, Trent Boult was better than his figures suggest; Adam Milne's opening five-over spell produced two for 12; Nathan McCullum was tidy and Mitchell McClenaghan, after shipping 15 runs in his first two-over spell, then took four for 21 in eight overs.
Three came in one over as Sri Lanka stumbled, partly down to fine catches from wicketkeeper Luke Ronchi, leaping spectacularly to his left, and Anderson, running and diving at deep midwicket.
At 101 for five, things were wobbly for New Zealand, after offspinner Sachithra Senanayake and swing bowler Nuwan Kulasekara caused problems.
However Anderson, playing some thunderous shots, found support from Ronchi and then Nathan McCullum.
The second game in the seven-match series is in Hamilton next Thursday.
