McCall's men had lost in the European Challenge Cup semi-final at Toulon seven days earlier and they were seeking a big response at StoneX Stadium.
They didn't get it immediately as Saints took a 10-9 half-time lead despite going down to 13 men following yellow cards for Alex Coles and Lewis Ludlam.
But Saracens came flying out of the blocks at the start of the second half, scoring five tries during the second period as they secured a 42-38 win.
It means Saracens are now certain to have a home semi-final in the Gallagher Premiership play-offs on June 11.
And McCall said: "It's a great group of players and a great effort to get 87 points to get a home semi.
"We were really gutted at how we performed (at Toulon) last week. Something was not quite right and maybe we were feeling a little bit pleased with ourselves after a few victories but we certainly got a punch in the face.
"We lacked accuracy in the first half and were disappointed not to score against 13 men, but it didn't bother us as we knew if we could cut out the mistakes then the tries would come so everyone was calm at half-time."
Saracens and England hooker Jamie George says he and his team-mates were actually very pleased with their first-half performance, despite going in at the break a point down.
George said: "The first half was actually pleasing. We put them under so much pressure in that first half and it was a lot more like the team we want to be.
"They scored, took their opportunity and they are going to do that because they are a good team, but what we need to do is focus on building.
"We let our foot off the gas in the last 20 minutes, which is really disappointing because we've done it a couple of times this season so we need to make sure we get that right.
"Everyone is going to talk about the first 20 minutes of the second half for us, but the first half was brilliant as well.
"We secured a home semi-final and that's going to be epic so we're excited about that already.
"We want that home semi-final, we want to be producing these performances for the fans and it's really exciting times ahead.
"We've got some steps to take but we're going in the right direction and that's the exciting part."