Midfielder O'Hara knows all about Bassong's qualities from their spell together with Tottenham.
O'Hara moved to Molineux during the 2011 January transfer window and now Bassong has made the temporary switch from White Hart Lane until the end of the season and impressed in a debut win at QPR.
O'Hara, who is optimistic of overcoming a groin injury in time to face the Baggies, said: "Seb really is a top-class international player. When Tottenham qualified for the Champions League, he played every game that season.
"I always said if we got Bassong in, he'd be a fantastic player for us, so I'm so glad that the chairman (Steve Morgan) and the manager (Mick McCarthy) managed to do that.
"You could see his quality against QPR. He's good on the ball, he's got pace and he's definitely going to strengthen us.
"He's a proper centre-half and he's a good ball player as well. He's an excellent defender and fair dos to the manager for getting someone of his ability."
O'Hara believes Wolves need 14 more points to clinch a fourth successive season of top-flight football.
He is also hoping to have the same impact as in the second half of last season after returning from a two-month absence following double hernia surgery.
O'Hara said: "I think we need another four wins and hopefully we'll get a couple of draws as well.
"We've got a fantastic squad and we shouldn't be where we are. We need to change it around but I still think we can make this season a good one.
"As for me, I'm looking to have that same sort of impact again as I did last year and help us stay up.
"Being out of the side for a couple of months means I feel fresh and really hungry to get back.
"It's a huge game against West Brom. We both need the points."
O'Hara knows Wolves have to improve their home form, having failed to win in the last six matches in front of their own fans since overcoming Sunderland in early December.
He said: "We need to play well at home and make Molineux a fortress.
We haven't done that, we've been disappointing at home, it just hasn't happened for us and I don't know why.
"The fans have been frustrated with our home form and the performances haven't been good enough. But we can correct in the last seven home games by getting it right."
McCarthy will be without Emmanuel Frimpong, who returned to Arsenal after rupturing knee ligaments, and the suspended Karl Henry while another midfielder in Dave Edwards is battling to overcome a thigh injury.