The Black Caps are fully confident skipper Brendon McCullum will be available when they resume their cricket World Cup campaign against Afghanistan.

During a typically blazing knock in New Zealand’s one-wicket win over Australia in Auckland, McCullum had bludgeoned 22 runs off seven balls when he took a nasty blow to his left arm from pace bowler Mitchell Johnson.

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He needed treatment before batting on, scoring a 24-ball 50.

Coach Mike Hesson described the injury as deep bruising and said McCullum should definitely be right by the time of the Afghanistan fixture in Napier next Sunday.

“It’s pretty swollen at the moment,” Hesson said.

McCullum gets hit on the arm during the Kiwis’ win. Photo: Getty

“We’ll make another assessment in a day or so, but all signs are that he will be fine.”

The Black Caps have fielded the same XI in garnering four wins from four matches.

Indications have been that the four players not used yet – Tom Latham, Nathan McCullum, Mitchell McClenaghan and Kyle Mills – would get game time next weekend or in the last pool match against Bangladesh.

But Hesson said selection was always a balancing act.

“When you have a week between games, if you leave out some of your key players, it can be two weeks before they play again, which is a long time,” he said.

“We’ll have to sit down and work out the pros and cons of both, but as we’ve said all along, all 15 are key players for us, and if they have to perform a role, I’m sure they will.”

Against Australia, two players who performed significant roles were paceman Trent Boult and top-order batsman Kane Williamson.

Boult took his maiden five-wicket bag in ODIs with 5 for 27 as Australia were skittled for 151.

In New Zealand’s chase, Williamson kept his composure while wickets tumbled at the other end, with pace bowler Mitchell Starc the chief destroyer with a career-best 6 for 28.

With six runs still needed and number 11 batsman Boult at the other end, Williamson played a shot that will not be forgotten easily, lofting a Pat Cummins delivery back over the pacemen’s head and clearing the boundary rope.

He finished on 45 not out.

Asked what he was thinking as New Zealand collapsed from the relative comfort of 4 for 131 to 9 for 146, Hesson admitted “there was quite a bit going on underneath”.

He said Boult, who came in as Starc had his second opportunity of the innings for a hat-trick, showed plenty of character to see out the last two balls of the over.

“At that point, Kane realised he needed to make a bit of a move,” he said.

“He had to play the shot he did in the situation. To go down the line of the ball and pick it up like that showed a lot of guts and a heck of a lot of skill as well.”

The win not only meant New Zealand regained the Chappell-Hadlee Trophy, but it also put them on the threshold of confirming a place in the quarter-finals.

AAP