To hell it was, Kalambay Humiliated him when he was close to shot. The best version Sumbu would do exactly the same to Watson, Benn and your boyfriend.
I've just watched Kalambay-Collins and it was a fantastic performance by Sumbu, he toyed with Collins at times, even more impressive considering the fight before he got a gift decision against Herol Graham.
Considering the trouble Collins gave Kalambay, and the fact Watson was a class or two above Steve, I see Watson faring favourably against Kalambay in '91; Kalambay simply unable to keep Watson off him for 12 rounds with no early body attack.
Those who are to argue Graham wasn't a master of boxing: He completely dominated a mid-career Mike McCallum (top 20 all-time lb4lb?) for six rounds, making McCallum look silly. That alone suggests he was. If Graham had boxed Kalambay with movement in their first bout instead of being aggressive, he would've ran away with it.
I could say I can't look beyond Kalambay struggling with Barkley for 15 rounds and Benn blowing him away in one round, with Benn having already been completely embarassed by Watson. Or Kalambay being knocked out by Nunn in a round, who struggled with Barkley for 12 rounds, who Benn blew out in a round, who was schooled by Watson. Styles do account.
(However I do feel Barkley would've beaten Graham for the WBA title, by outlasting him down the stretch and grinding him out.)