Robert Helenius still considers Anthony Joshua an elite-level heavyweight.

Joshua’s upcoming opponent suspects, though, that the former IBF/IBO/WBA/WBO champion remains impacted by the lingering psychological effects of his technical-knockout loss to Andy Ruiz Jr. and his brutal battle versus Wladimir Klitschko, during which Joshua got off the canvas to win by TKO six years ago. Joshua’s less aggressive approach is also partially attributable, according to Helenius, to changing trainers, most recently from Robert Garcia to Derrick James.

Helenius thus expects to encounter a more tactical fighter Saturday night at O2 Arena in London than he fought in numerous sparring sessions during the early part of Joshua’s professional career.

“I respect him a lot,” Helenius told DAZN broadcasters Darren Barker and Ade Oladipo after a press conference Wednesday in London. “Of course, I think he’s a little bit gun-shy from his earlier fights. Or I don’t know if it’s gun-shyness anymore. I think it’s more of his change in his technique with a new trainer. And they’re making him [make] more movements, more checking around, not going in aggressively, like he did in the beginning of his career. So, he’s grown as a boxer as well. … I respect him tremendously, and I’m gonna have to be a hundred percent [there mentally] to get this win.”

Helenius, 39, stepped in for Joshua’s rival, Dillian Whyte, on less than one week’s notice because the Voluntary Anti-Doping Association reported “adverse analytical findings” while testing London’s Whyte (29-3, 19 KOs) for performance-enhancing drugs.

Ruiz (35-2, 33 KOs), who was also a late replacement for a Joshua opponent that failed PED tests, dropped Joshua four times. Joshua was a 20-1 favorite to beat Ruiz in June 2019 at Madison Square Garden in New York, but Ruiz got up from a third-round knockdown and sent Joshua to the canvas twice apiece in the third and seventh rounds on his way to a seventh-round stoppage.

Helenius, however, doesn’t believe he needs to knock out Joshua to beat the British superstar in the venue where the 2012 Olympic gold medalist has fought the most as a pro.

“I don’t think so, no,” Helenius said. “I don’t think so. I have to be active and then explosive and elusive. Really, movement, speed is gonna be key.”

Handicappers have established the 33-year-old Joshua as a 16-1 favorite entering a 12-round main event DAZN will stream worldwide. DAZN’s coverage of the Joshua-Helenius undercard is scheduled to begin at 7 p.m. BST in the United Kingdom and 2 p.m. EDT in the United States.

Helenius (32-4, 21 KOs) will box for the second time in eight days when he squares off with Watford’s Joshua (25-3, 22 KOs). The Swedish-born contender stopped Finland’s Mika Mielonen (6-1, 6 KOs) in the third round of a scheduled eight-rounder last Saturday night at Olavinlinna, a castle in Savonlinna, Finland.

Before he beat Mielonen, the 6-foot-6, 250-pound Helenius hadn’t fought since suffering a crushing first-round knockout loss to former WBC champ Deontay Wilder (43-2-1, 42 KOs) last October 15 at Barclays Center in Brooklyn.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.