Christchurch, New Zealand: Brendon McCullum launched his farewell tour in rollicking form Saturday with a whirlwind 55 to set up New Zealand's seven-wicket win over Sri Lanka in their opening one-day international in Christchurch. 

In a 25-ball stay at the crease, McCullum smacked 11 fours and one six to have Sri Lanka on the ropes before he departed with New Zealand only needing a further 81 runs in 40 overs.

Martin Guptill posted his 26th half-century on his way to 79 off 56 deliveries while debutant Henry Nicholls was not out on 23 when the innings ended at the end of the 20th over.

New Zealand were set a modest 189 target after Matt Henry destroyed the cream of the Sri Lankan top order in a brief spell of 16 balls when he took four wickets for two runs. 

Sri Lanka were eventually all out for 188 in 47 overs on a wicket that promised runs galore, and New Zealand knocked off the target with ease.

The big-hitting McCullum, who announced before the five-match ODI series began that he will retire from international cricket in February, lived up to his pledge to bow out on top of his game. 

His whirlwind opening partnership with Guptill brought up the New Zealand 100 inside 10 overs. 

When New Zealand reached 53 without loss after six overs, Sri Lankan captain Angelo Mathews put himself on to try to arrest the run onslaught. 

McCullum had other ideas and took 16 off Mathews' over and 12 off Ajantha Mendis in the next over to put Sri Lanka out of the game. 

Mathews said when he won the toss he wanted to bat to get first use of a pitch that "looks like a belter".

But the wickets started falling early with a 98-run stand by Milinda Siriwardana and Nuwan Kulasekara for the seventh wicket their one partnership of note.

They fell from 13 without loss to 27-5 and then 65-6 before Siriwardana (66) and Kulasekara (58) stemmed the rot.

Siriwardana's dismissal started the final slide in which the last four wickets fell for 25 runs. Dushmantha Chameera, who was not out 13, was the only other batsman to reach double figures. 

Adam Milne, having fully recovered from the heel injury that sidelined him in the World Cup, was bowling near the 150kph (93mph) mark and while he tied the batsman down at one end, Henry did the damage at the other. 

Inside three overs he removed Tillakaratne Dilshan, Lahiru Thirimanne, Mathews and Dinesh Chandimal. 

Dilshan (nine) top edged the ball to midwicket where Nicholls celebrated his international debut with a catch above the head, Thirimanne faced 19 deliveries for one run and Mathews went first ball. 

Chandimal was dropped on five off Milne's bowling, but Henry claimed the wicket four balls later without addition to the score to finish with four for 49. 

Doug Bracewell, who broke up the Siriwardana-Kulasekara partnership, had figures of three for 37.