MacGinty notched 15 points and provided an assist for Marland Yarde's try as he steered Sale to a Gallagher Premiership success.
Saints only had two James Grayson penalties to show for their efforts as they suffered a second successive defeat.
And Sale boss Sanderson was delighted with how his side bounced back from their loss at Worcester as MacGinty showed his class.
"There was some honesty at the start of the week, which translated into some physicality at the end of the week," Sanderson said.
"The defeat at Worcester was a slip rather than a fall, and I give credit to Worcester because they came out and were a bit more hungry for it.
"The boys who came back in gave us a little bit of experience.
"I've still got faith in the other lads and I'm still going to rotate them and play them, but on a wet night like this, you tend to turn to those players who have been there and come through it. And they have stepped up today.
"AJ (MacGinty) was magic. I always like to get the bench on but he was in such a good flow and I just wanted to leave him on and he kept kicking the goals.
"We haven't really seen AJ this season and he's pretty much the finished article.
"He got back into his groove and that's the AJ I expect to see for the rest of the season.
"He just pulls the strings like a good 10 does."