Usain Bolt Celebrates Pro Soccer Goal with 'Shoot' Dance

Usain Bolt was Usain GOOOOOAAAAAAAAAALLLLLLLLTT in his Australian pro soccer game on Friday ... hittin' the back of the net TWICE ... and celebrating with the "shoot" dance!!

The 8-time Olympic gold medalist suited up for the Central Coast Mariners -- wearing a #95 jersey -- and he BALLED OUT in his second appearance for the club ... scoring 2 goals.

Of course, Bolt christened the goals with his signature "lightning bolt" pose for the first goal he scored, an hour into the match ... then followed up with the BlocBoy JB dance for his 2nd goal in the 69th minute.

BTW -- even though he's on a trial with the Mariners, Bolt is serious about this whole soccer thing ... and he's even told TMZ Sports he'd be down to join the MLS -- if they pay up.

The challenge for Bolt, he's gotta convince the old school soccer dudes he's for real -- because when we spoke with Alexi Lalas about Usain joining the MLS, he basically told us there's no shot.

But, if Bolt continues to torch defenses ... ya gotta think it's a matter of time before he gets a contract offer.