Chelsea won 1-0 thanks to Enzo Fernandez's early header to end a week that saw former manager Liam Rosenior sacked and the players accused of undermining him.
"I thought our character, our fight and our drive was brilliant," McFarlane said afterwards.
"We speak tactically a lot but tactics go out of the window at times and I thought the fight, winning second balls, headers, defending set-pieces – the character of the group was exceptional.
"That's been questioned a lot. And rightly so at times, maybe, but that is us at our best and we have to show that level as often as we can. This group is massively capable of that."
He added: "That group has got massive character. You don't beat PSG in the Club World Cup, Barcelona in the Champions League, and loads of other games… the character shouldn't be questioned.
"I understand why, but there's a lot of mentality, winners in that changing room. I'm really happy we could show that today."