But the loss of Ferris to the sin-bin for killing the ball assisted the Naka Drotske-coached home side in battling their way back into contention.
The Super 14 outfit scored two tries before half-time and managed to outscore the Lions by three tries to two over the 80 minutes.
In the end, the Lions needed a 100% place-kicking return from 16-point out-half James Hook to pull them through, and even then they had to survive a late, missed drop goal attempt from the Cheetahs' Louis Strydom.
The relief was palpable amongst the Lions supporters but Ferris and tour captain Paul O'Connell were both confident that the tourists would have been able to retrieve the situation had that late kick gone over.
Ferris said: "It was very close. At one stage it was swinging towards the poles and it missed by two feet max.
"If it had gone over, however, I was confident we could come back from that."
O'Connell, who put in another impressive individual display, said: "I'm happy to win, but a bit disappointed with the performance.
"We started very well and played some good stuff, but then we went to sleep.
"They competed well at the breakdown and got a lot of turnovers."
The breakdown was an area the Cheetahs managed to frurstrate the Lions in as the game wore on, and O'Connell knows his players cannot afford to be as sloppy there again with the Test series looming large.
"Maybe we stopped putting in as many numbers at the breakdown - you need numbers there, to be low and aggressive, and we didn't do that," he said.
"Turning the ball over killed us. They can take momentum out of your team and give the other team belief.
"We've had a great buzz, and the guys were very enthusiastic, but for nine of the guys it was their first game in a while, so to get away with the win was important.
"Decisions will go against you in a rugby game. We needed to be a bit more clever than we were when Stephen was in the bin.
"But a win is a win and we move on from here."
Giving his reaction, Lions head coach Ian McGeechan picked out some bad points but was reasonably pleased his men had come through on the right side of the result after another tough challenge.
"We got ourselves into a good position and didn't develop it as we could have done," said the Scot.
"The breakdowns became a bit of a lottery and took a lot of momentum out of the game.
"We knew the games were going to get increasingly tougher, and I think it was a good challenge.
"You can never underestimate how important a win is to the squad.
"The start was very good, but it became stop-start after that, which disappointed us. I don't think the ball in play time was very high."
The Lions' failure to build on the momentum of last Wednesday's landslide victory over the Golden Lions was one of the most disappointing aspects of this performance in Bloemfontein.
Sleepiness setting in, loss of concentration and discipline, call it what you will. But a similar slip-off in performance levels will leave the Lions chasing shadows when they take on World champions South Africa.
"There was a really good buzz after Wednesday and I thought that we carried it through for the first 20 minutes," Ferris reckoned.
"We were offloading well, tackling really well and just playing some good rugby.
"But the concentration went and obviously my sin-binning didn't help. We had a 14-point turnaround during that time but the boys hung in there well.
"I suppose, though, if we play badly and still win, we'll take that."
The Dungannon clubman did praise the Cheetahs for the quality of their play and how difficult an afternoon they made it for the men in red.
"We'll probably ship a fair bit of criticism for the performance because we were 20 points up after 20 minutes and if we'd shown a bit more composure and grit we could have gone on and put a fair few more points on them.
"But fair play to the Cheetahs, they're a very tough side and were very competitive around the pitch.
"There's a lot of capped players in their side so we were always going to be in for a tough day."