And O'Connell, who led The Lions in their opening tour against the Barbarians just over a week ago, reckons the latest step on his third tour will have short and long-term benefits for everyone involved.
"It was exactly what we needed," said O'Connell, who struggled with a back injury for much of the season prior to his Lions call up.
"Looking from the sideline, the Reds brought massive intensity to the breakdowns at the start of the game and, after the game in Perth, that was exactly what we needed.
"They were tough conditions as well, which was a bit of a reality check of how hard it's going to be.
"Three games in, a lot of us were (in camp) for three weeks and you have nothing to review. You're reviewing training but now we have three games to review, three different types of games as well, so there will be a lot of learning from that and, hopefully, we'll improve a lot from here.
"I wish I had more games under my belt coming into the series. After the selection, to get the (Munster v) Zebre game and get in for the Baa Baas game in such tough conditions and get whatever I got in that - 60 minutes - I was delighted to play in that game, even though the conditions were so hard.
"My game is based on fitness and the more of those hard games I can play in when that is put under pressure and I can build my fitness base up to where it needs to be, the better."
While Saturday's game gave The Lions just the kind of test head coach Warren Gatland had been asking for, it came at a cost as Tommy Bowe broke a bone his hand.
His injury came hot on the heels of tour-ending setbacks for loosehead props Cian Healy and Gethin Jenkins, but O'Connell insists the squad have to put those disappointments behind them and stay positive in the lead up to the three-Test series with the Qantas Wallabies.
"I think we're in good shape. You'd rather not have these injuries but they were always going to happen," added O'Connell.
"We were delighted to get through the Baas Baas game with no injuries but the few that have come this week with Cian, Gethin and Tommy, it isn't ideal but we've just got to deal with it and get on with it.
"I think you have to be positive. You look at the guys that have come over; (Alex) Corbisiero and (original selection) Mako (Vunipola) are touch and go for the English team when they play so I don't think it weakens us in any way.
"You've got to be positive about it and they had spoken early on saying that this was going to happen, guys were going to be brought over, guys were going to get plenty of chances, so you've just got to deal with it and get on with it.
"The guys that get injured, they are very disappointed obviously, but you've just got to get on with it. They move on fairly quickly, they start planning what they've got to do to get it right, and the squad kind of has to move on as well. You're disappointed for them but the squad has to move on."