Shibasaki's career was in limbo before the start of the season when he was put on a development contract at the Broncos.
The NRL journeyman, who has had four clubs and a stint in Japanese rugby, scored two tries in another sensational display to give the Broncos a 3-1 start to the season in front of a sold-out crowd in the "Battle of Brisbane". He was also the winner of the "Battle Medal".
Fellow centre Kotoni Staggs, famous for his match-winning try in the inaugural Battle of Brisbane in 2023, scored a crucial individual try on the cusp of half-time in a typically blockbusting display.
The Dolphins had a crucial call go against them in the first half when half Isaiya Katoa appeared to secure a 40/20 when the Broncos led 10-6.
Broncos winger Selwyn Cobbo was clearly over the sideline when he tapped the ball back in-field. The Broncos scored up the other end minutes later through Staggs.
Broncos back-rower Jordan Riki was put on report for a shoulder to the head of Dolphins winger Jack Bostock, who left the field for an HIA on the cusp of half-time. Riki was fortunate not to be sent to the sin bin.
Those moments aside, the Broncos were the better side and deserved their win on a rainy Brisbane night.
The Dolphins failed to take their chances and were far too slow while in possession despite the best efforts of centre Herbie Farnworth, who was his side's best.
No side in premiership history apart from Newtown in 1933 has won a title after losing the opening four games of a season.
The hosts played their most up-tempo football of the year in the first 12 minutes but couldn't crack the Broncos' defence
Brisbane duo Reece Walsh and Staggs held up centre Farnworth with desperation.
The Broncos absorbed the pressure and with one chance put the knife in.
Five-eighth Ben Hunt delayed a pass perfectly to send second-rower Jack Gosiewski through a hole and Shibasaki finished it off.
Hooker Cory Paix took advantage of dreadful marker defence to make it 10-0 after 15 minutes.
Katoa conjured a response by straightening up the attack and forward Max Plath dived over under the sticks.
Staggs, returning from a hip-flexor injury, did it all himself with a blockbusting run. He pointed at the turf with both hands to signal that Suncorp Stadium belonged to the Broncos.
Brisbane's 16-6 lead at halftime was extended after the break when Walsh put Shibasaki over for his second.
Dolphins centre Jake Averillo scored a 90m try after a quiet night to keep the scores close.
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