The 31-year-old joined from Manchester United late in the transfer window as he reunited with Martin Jol, who managed Tottenham during the Bulgarian's time at the north London club.
Berbatov rejected the likes of Juventus and Fiorentina to move to Craven Cottage, where he netted his first two goals in the 3-0 defeat of West Brom on Saturday.
Riise could not help but be impressed by his new team-mate's performance for the Whites, and believes it bodes well for the future.
"For Fulham to have a player like him at the club is amazing," he told the club's official website, www.fulhamfc.com.
"It just proves that we're working hard to push the club forward.
"He came in and scored two goals on his home debut and you can't ask for more than that.
"He's settling in well and all the boys are pleased to have him in the team.
"We'll try and make it as easy for him as possible at his new club."
Both of Berbatov's goals came after good work from Alex Kacaniklic, who has been handed the unenviable task of replacing Clint Dempsey on the left wing following his move to Tottenham.
The 21-year-old has impressed in his performances so far and left-back Riise believes the pair can build a decent relationship.
"Last season, I had Clint in front of me and we had a good relationship," the Norway international said.
"We're going to miss him but Kaca has come in and we work well together.
"He works hard, he's young and keen to learn. I like having him in front of me because I know he'll do a lot of good things.
"It looks good for the rest of the season."
Attention now turns to Saturday's trip to the DW Stadium, where Martin Jol's side will be looking to get their first point of the season away from west London.
The Cottagers suffered league defeats at Manchester United and West Ham, but are hoping for a change of fortunes at Wigan as Riise steps up his return to full fitness.
"I haven't trained as much as I wanted," he said. "I was out for about 10 days because of the injury and then I played a game [at West Ham].
"Then I was on international duty, before returning and playing at the weekend, so I'm looking forward to a good week of training before the next game at Wigan.
"They've [Wigan] done well so far. They've got a great manager but they've lost a couple of players such as Victor Moses.
"We go there to try and win and get three points and it's a game that if we play our best football, we'll be in with a shout."