This wasn't a vintage performance, nor a particularly exciting one ala Paulo Aokuso's knockout of the year contender on the undercard at light heavyweight. It didn't need to be, so long as the former WBO junior middleweight champion emerged victorious.

After all, he admitted waking up at 4 a.m. on fight day with his mind racing about the possibilities before a high-pressure headliner in his hometown. Having masked it well during fight week, a fourth defeat here would have been curtains for his career.

Instead, Tszyu can enjoy his holiday in Thailand with wife Alexandra knowing options aplenty await him in a new weight class.

WBA middleweight champion Erislandy Lara (32-3-3, 19 KOs) was named, newly upgraded WBO beltholder Denzel Bentley (22-3-1, 18 KOs), too, with No Limit chief George Rose excited about what's to come after some rest following three successive training camps.

"I was starving myself to get to 154. I feel a big difference at 160," Tszyu began at Sunday's post-fight press conference.

Spence (28-2, 22 KOs) announced his retirement immediately afterwards in the ring, before doubling down when quizzed by media backstage.

"Errol is a legend, but how I felt in front of him felt completely different [than before]. Felt like I could stop him at one stage. He was in survival [mode] half the time running around. I've been dropped three or four times in the first round so my thing is I get too excited very quickly, need to slow it down and take the fight slowly, defense first and then offense will go from that."

The former unified welterweight champion threw more punches than Tszyu in each of the first five rounds, though the story was much different after that.

Tszyu seized control in the second half, aided by success behind his right hand and left hooks.

Spence absorbed his best work, though couldn't hurt the 31-year-old enough to keep him from pressing forward. Inspired by trainer Ronnie Shields' instructions, Spence emptied the gas tank with an inspired 11th stanza but had nothing left and didn't connect on any of his 14 punch attempts in the final frame.

Tszyu landed the harder shots, with a 117-59 edge in power punches over the final seven rounds per CompuBox, while connecting the most of any Spence opponent.

Tszyu even asked for Spence's advice on how he could improve.

"He said stay patient. 'When you're not rushing in, you're very dangerous and when you wait, you're a very good counterpuncher with fast hands,'" Tszyu said.

Although he didn't get the stoppage that many expected, given how off-balance Spence looked for sustained periods, it was a welcome debut under trainer Jeff Fenech.

"His energy, corner advice, he's an unbelievable coach," Tszyu said. "He's a big leader, takes charge and I felt very comfortable with him. I thought it'd take a few fights to adapt, but even after two weeks we started flowing and I'm very blessed to team up with a legend like that.

"His energy, gameplans, you've got to do this and that, just refreshing. He's an idol, not a padholder. He looks at things from afar like [esteemed rugby league coach] Wayne Bennett. You definitely feel it, and from previous fights it's a big change.

"You can fight on different stages around the world but to come out to something like that [atmosphere], Aussie boxing history and legacy-defining type stuff is surreal. I definitely want to make some super fights happen."