"I boxed the way I needed to and it was a good first fight back against a tough campaigner."
Business and family commitments forced O'Brien, a father of two, to retire in 2014. Last year his workmates told him if he wanted to train fulltime they could run his Bo's Mows lawn mowing business for him.
"I've got to thank them, my clients and my partner [Lisa Timu] for allowing me to pursue my dream," O'Brien said.
He is hoping to secure another fight next month before taking on Tauranga-based professional Gunnar Jackson in May. Jackson has had more than 40 professional fights and was once ranked among the top 10 on the World Boxing Organisation rankings.
In January, 2014, Jackson had the biggest fight of his career against four-time world champion Anthony Mundine of Australia. Jackson lost by a unanimous points decision.
"Gunnar is going to be a massive step up for me. I'm more of a boxer than a brawler and Gunnar is too so I'm picking it will be a nice technical fight," O'Brien said.
"Hopefully the opponent I get next month will be similar so I get the best preparation possible for Gunnar," O'Brien added.
The former holder of the New Zealand Professional Boxing Association's (NZPBA) light-middleweight title, O'Brien, started his amateur career as a 14-year-old. He won 10 of his 20 amateur fights and in 2007 he won the national 69kg welterweight title.
In 2006 O'Brien was second in the 66kg light-welterweight class at national level.
O'Brien's trainer Rod Langdon was thrilled with his display against Mishra.
"He did everything I wanted him to do. I think there was a mistake by one of the judges and Beau's victory was more convincing than a split decision. Shiva was a bomber so Beau took control of the ring, moved him around and he missed most of his bombs."
Another of Langdon's professionals on a comeback trail, Kiki Toa Leutele, 24, had his first fight in two years and scored a third-round TKO against Canterbury heavyweight Ali Loto in a bout which was scheduled for six rounds. Loto was 10kg heavier than Leutele and had won three of his previous four pro fights.
Leutele's only previous professional fight was in 2016. He was the 2011 national youth super-heavyweight champion.
"Kiki put Ali down twice before the referee stopped the fight after the third time. Kiki is pretty focused on his boxing again," Langdon said.
Napier Boxing Club's Katie Hatton had her first corporate fight at the event and lost by a unanimous points decision.
"Considering she only had three weeks of training Katie did well," Langdon added.