The Ivory Coast international was deployed in an unfamiliar right-back role with United in the middle of an injury crisis.
However, he didn’t last long and was withdrawn from the action after just 36 minutes having picked up a knock.
Bailly had been having a torrid time against United old by Angel di Maria.
And Ferdinand reckons Bailly’s injury actually helped Ole Gunnar Solskjaer in the end.
“It would have been negligent to keep Bailly on the pitch to be honest,” Ferdinand said on BT Sport.
“It’s a blessing he got injured and had to come off.”
Bailly was arguably at fault for PSG’s equaliser after Romelu Lukaku put the Premier League side ahead.
Owen Hargreaves was similarly scathing about the former Villarreal defender.
“Credit PSG it was a good reaction from going 1-0 down,” Hargreaves said.
“They’ve (United) had issues down that right side all half.
“Bailly needs to step up and get in line with his defenders.
“The worst part is that in the second phase he’s got to get in there and deal with it, he’s the defender but he doesn’t.”
United eventually won the game 3-1 and booked their place in the quarter finals on away goals.
England international Marcus Rashford showed nerves of steel to convert a late penalty.
Speaking after the clash, Ole Gunnar Solskjaer said he was nervous for the young forward.
“That’s the Champions League, it’s what it does,” he said.
“Last night with Real and Ajax was our team-talk, it was probably theirs too.
“Last year it was Real and Juventus, there’s been PSG and Barca too.
“It’s this club, it’s what we do. That’s Manchester United.
“There’s always mental doubt. Our boys are young and fresh which gave us more energy when we needed that goal.”