Slamma are now just three points behind with a game in hand – and with another clash with Celtics still to come.
The two other matches were also tight with Warriors beating Sentinels 68-64 after the match went into overtime and Storm snatching an 88-79 win over Island Juniors.
Celtics 73, Slamma Jamma 78: Both teams started playing man-for-man defence but with Slamma applying more pressure to take an early 7-4 lead before Celtics rallied to win a low scoring quarter 11-8.
The second quarter saw Celtics change their defensive tactics – which stopped Michael Pusz from scoring but not the rest of the team.
An ankle injury to Michal Niedziatek half way through the quarter left Slamma with five players but they still piled on 22 points to 12 with Slamma newcomer Osipiuk scoring nine inside to help his side to a 30-23 lead at the half.
The third quarter saw tiredness creep in but Slamma posted 30 points – with Osipiuk and Pawel Zalewski both scoring eight.
In reply Celtics managed 23 with Chris Byrne notching eight and and Steve Brady seven as Slamma went further ahead at 60-46.
In the fourth quarter the game promised to be closer.
Halfway through Slamma’s lead was ten points but that was cut to six and then five as Slamma held on for a crucial victory.
Noteable scorers were Dave Middleton (24), Chris Bryne (20) and Steve Brady (15) for Celtics and Osipiuk (25), Michael Pusz (15), Pawel Zalewski and Rafal Kleszko (13) for Slamma.
Sentinels 68, Warriors 64: Warriors have won the two previous meetings of these sides this season and held a two-point advantage at the end of the first quarter.
But in the second Sentinels dominated to go 11 points ahead as Ryan Driver scored 12 points The third quarter was closer with Warriors’ skipper Greg Ruellan shooting from distance.
But Sentinels still increased their lead to 15 points.
Warriors came to life in the fourth quarter and pressed hard.
Gerado Garica and Mat DuBourg were exceptionally strong on offence and, amazingly, Warriors tied the game at 62-62.
With both teams tired Warriors had captain Greg Ruellan fouled out and Sentinels lost Colin Moore, Tshepo and Alex Henderson.
Paul Duckworth then stepped up to lead the Warriors offence and six points from him gave his side an unlikely victory.
Island Juniors 79, Storm 88: Storm have hit a run of form of late and made the most of the Juniors turnovers to score some quick points and finish the first quarter 26-12 ahead.
In the second quarter Duncan Prince for Storm stepped up his game, driving strongly to the basket to score 12 points with Michael Kreft also picking up eight.
The Juniors responded through Derek Perriera and Liam Barry but the half finished 53 to 33 to Storm.
The third quarter was by far the best for Juniors as Nick Dingle netted 12 points with Alex Henderson picking up important rebounds.
But Storm fought back with Kevin Bicknell picking up more turnovers to finish 69-53 in front.
In the fourth the Juniors went flat out to get back in the game as Middleton rebounded both ends of the court and unleashed some big three-point shots.
But Storm’s Prince scored eight points in an exciting climax.
