It's basketball's blue bloods versus a bunch of orange roughies in the Trafalgar Centre tomorrow.

The Fico Finance Nelson Giants are Bartercard national basketball league royalty, always there or thereabouts at playoff time, while the Southland Sharks are the competition's upstarts – new money who entered the league this season and have ruffled a few feathers along the way.

With crucial playoff positions hanging on the outcome of the final regular-season round, Giants management have asked for fans to dress in blue to help their team over the line.

Three games ago, the Giants were contending for first place and home court advantage through the semifinals and finals.

A loss to Manawatu extinguished that ambition, while last Friday's disappointing defeat by the Harbour Heat cost them any real hope of third place.

The best the Giants can hope for now is fourth, but they could still slip to fifth or sixth and be facing a road trip quarterfinal early next week.

Coach Chris Tupu said crowd support would play a big part in earning that extra home game.

"Phill [Giants captain Phill Jones] said it all last week – we didn't show up, and the crowd deserved better," Tupu said.

"Whether or not the crowd comes on Friday isn't up to me, but I hope we get their support again.

"Having said that, I'd understand why the fans might think we've let them down two home games in a row."

Tupu is at a loss to explain last Friday's battering.

The Giants, needing a win to be in line for a top two finish, were uninvolved for most of the match, lethargic on defence and uninterested in rebounding, while Jones had 40 points as he played a lone hand on offence.

The team made the right noises in the week leading up to the Heat game but didn't back the words with deeds, Tupu said.

"I can't explain what we saw.

"All I know is that the lack of urgency was unforgivable, and I hope I am never involved in a performance like that again."

Southland have two chances to crack the top six in their first season in the NBL.

If they can't beat the Giants, they can still make the playoffs in their debut season by beating Manawatu on Saturday.

Tupu is expecting the Sharks to throw everything at his side tomorrow, though.

"They have all the pieces – great guards, a very capable swingman, good young bigs," he said.

"They have been playing very well but we're not going to roll over for them.

"There's a home quarterfinal at stake, and if that's not motivation enough for my guys, then they should probably be looking elsewhere."

Giants swingman Darryl Jones is a day-to-day proposition with a hamstring pull that will be assessed before tipoff tomorrow.

If he can't play, Sam Dempster, who turns 20 this week, is likely to see more court time.