"Both of them are like players you see in those video games," Hamren told a news conference at the Friends Arena where Sweden meet Argentina on Wednesday in front of a sell-out crowd.
"They do things you don't think it's possible to do. Two extremely talented and really, really good football players."
As both teams held training sessions under the closed roof of the new stadium, there was little to suggest that the rumoured rift between Ibra and Messi during their time together at Barcelona still existed.
"Leo is a fantastic player, he's probably the best player in the world," Ibrahimovic told reporters. "He is winning all the prizes, he's winning as an individual and I think it will be a great game."
Three-times world player of the year Messi did not speak to the press and has kept a low profile since arriving in the Swedish capital.
Fans and photographers alike have had as much luck as most defenders when trying to pin him down and security around the arena was tight as locals tried to get a glimpse of him during Argentina's training session on Tuesday.
But the Swedes are hugely proud of their own captain too and they are hoping he will repay their faith with a display similar to that which he produced against England in November.
In the first game at the new stadium, Ibra hauled Sweden from behind with a stunning four-goal salvo to beat England 4-2, rounding it off with an outrageous scissor kick from well outside the penalty area.
The Friends Arena, named after an anti-bullying campaign, is an apt title for the new 50,000-capacity stadium, and there was plenty of mutual respect on display as Argentina coach Alejandro Sabella praised Ibrahimovic.
"He's a great player because he has physical strength, is tall, good in the air, he makes the most of rebounds, he has all the skills to complicate [things]," he told a news conference.
"He can score in all kinds of ways, even with free-kicks as against England, which he did from 35 metres."
But Sabella said his side would not be changing their defensive game-plan to combat the Swedish captain.
"We have to be especially careful faced by the quality of a player like Zlatan, but the fact that he's playing doesn't change my idea of how to defend."
The friendly marks Sweden's final outing before their first competitive game in the new stadium against Ireland in a World Cup qualifier on March 22.
Ranked third in the world, Argentina will face Venezuela at home in their next match.
