Undermanned and overwhelmed, the Nelson Giants limped home from their pre-season basketball tournament in Christchurch at the weekend with a to-do list as long as coach Chris Tupu's sleeve.

The Fico Finance Giants lost American forward Michael Harrison to a serious ankle injury on the first play of the first game, a 70-65 loss to the Southland Sharks on Friday, and spent the next day shuffling players into unfamiliar positions to make do. Nelson looked strong against Otago, winning by 30 points, but suffered by a similar margin three hours later in a lethargic loss to tournament hosts, the Christchurch Cougars.

The early loss of the 2.06m Harrison meant the likes of regular point guard Josh Bloxham saw time at the small forward spot as Nelson ran three point guards at once, while reserve shooting guard Nico Ritschny had to fill in at the power forward spot at odd occasions.

Harrison had X-rays on the ankle on Saturday and has suffered soft tissue damage, with no break, but he might still be sidelined for a lengthy period.

"Losing Mike so soon in the piece meant we were constantly reshuffling," Tupu said. "It offered plenty of opportunities for players to show themselves and I saw a few really positive performances."

Standouts included Junior Tall Black Bloxham and rugged forward Sam Dempster, who stacked up 25 points and 11 rebounds against Otago.

"Sammy was awesome both ends of the court, JB [Bloxham] was one of our leaders and we had patches from Mike Fitchett and Benny Wright. We just really missed Mike and three more guys [Phill Jones, Mika Vukona, Tony Rampton] who we would expect to have in our starting five for the national league."

Development player Tom Ingham got court time against Otago and managed to knock down four three-point shots against the Nuggets' zone defence.

Tupu cited defence and mental focus as two areas where the Giants let themselves down, particularly in the 105-71 loss to the Cougars, who were near full strength.

"There's a lot to work on, a whole lot. You make an allowance for the fact that we had to reshuffle constantly and play guys out of position – sometimes way out of position – but there's no excusing the lack of mental sharpness and poor defence.

"Those things are about staying focused and playing hard and we certainly got smashed by Canterbury."

The Cougars won all three of their games while the Giants, Sharks and Nuggets managed a win apiece.

The Fico Finance Nelson Giants' NBL campaign starts on the road against champions Waikato on March 4.