Tasmanian basketball royalty Kathy Foster says it's "absolutely amazing" the Tasmania JackJumpers have qualified for the NBL finals in their first season.

The JackJumpers sealed their play-off spot in dramatic fashion on Sunday night when South East Melbourne Phoenix defeated the Perth Wildcats in overtime.

The team has become the first to complete the feat since the Gold Coast Blaze in 2008.

Foster, a 1984 Olympian and the first Tasmanian woman inducted into the Australian Basketball Hall of Fame, attends every JackJumpers game.

"I actually had a bit of a feeling that it might happen, I don't know why, I was too scared to say it out loud but I sort of thought maybe it is their time that they will make the finals," she said.

After 25 years without a Tasmanian NBL team, the former Hobart Islanders player said it was fantastic to see the state not just back on the national stage, but thriving.

"We've been in the wilderness for quite some time and Tassie has been a bit of a joke as far as basketball is concerned, and it's just absolutely great to see it back," she said.

"And young kids playing basketball and wanting to play basketball and talking about basketball, it's fantastic."

'You couldn't script it any better'

JackJumpers chief executive Simon Brookhouse told ABC Radio Hobart he was thrilled with how the team had performed.

"We're a bit small in terms of basketball teams, we're a bit shorter than a few of the others, but their grit and their determination are second to none," he said.

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"One thing that I think they've shown through all year is that the boys never give up.

JackJumpers fans erupted with elation at the result, which required the team to win its last four games and the Wildcats to lose its final two.

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They will now play Melbourne in a three-game series, kicking off on Thursday, with a home game to be played on Saturday.

Fan Nyal Merdivenci captured a video celebrating the wild result, exclaiming "woo, go JackJumpers".

"Just unbelievable, you couldn't script it any better, we booked flights and secured tickets for Thursday night," he said.

Miriam Archer Nichols posted on social media: "The best news ever for all Tassie, and the guys, great coaches, and staff. GO JACKJUMPERS."

Tourism Industry Council of Tasmania boss Luke Martin and former Premier David Bartlett were also among many prominent Tasmanians cheering on the team on social media.

A video of JackJumpers players celebrating as South East Melbourne knocked the Wildcats out of the play-off race has also gone viral.

Super-fan Simon Hall was glued to the Perth clash while out for dinner with his family.

Mr Hall's fandom extends to scheduling the birth of his youngest son Spencer around the team's fixture. 

"Eight days old, he was sitting court side with us for the rest of the season and I'd like to say he's the turnaround in the season," he said.

"They were [two wins, 6 losses] when he was born, since then they've been 15 and 5."

Mr Hall has been court side at every game this year and will attend the play-offs.

"I'd like to think I'm the number one fan, or up there."

He said he was immensely proud of the JackJumpers' efforts.

"Everybody said when they first started out that the team was going to struggle," he said.

"Seeing the way they've put this team together and they all play well together and the way they've engaged the fans and the community, that's great," he said.