The Frenchman started on the bench once again, with Howe sticking with the side that has served him so well in the Premier League in recent weeks.
But a double change was made midway through the second half, and it proved to be decisive. Newcastle now take a 1-0 lead back to St James’ Park, and that might not have been possible without Howe’s substitutions.
The Toon boss replaced Callum Wilson and Joe Willock with Alexander Isak and Saint-Maximin in the 67th minute, and that appeared to be the moment that inspired Newcastle to victory.
Isak will hog the headlines for his role in Joelinton’s goal, but Saint-Maximin was hugely impressive too.
Eddie Howe praises Saint-Maximin impact
After the game, Howe spoke to NUFC TV. He addressed the substitutions that he made, and praised ASM for his contribution off the bench.
“They all improved our performance [the substitutes],” Howe said.
“Alex, obviously for the goal it was a huge moment.
“But Allan…Maxi, I thought he was really good with his decision making when he came on and he gave us a different dimension.”
ASM looked back to his exhilarating best
It has been a long time since we have seen Saint-Maximin play like that. The 25-year-old has endured a tough season due to injury, and has struggled to get back in the side since returning to fitness.
But his cameo against Southampton was his best in a long time. He added spark and flair, and made a difference every time he got on the ball.
It was the Frenchman who got Duje Caleta-Sar sent off. He drove at the heart of the Southampton defence after picking up possession in his own half, but was fouled on the edge of the box by the Croatia international.
It resulted in Caleta-Sar getting his second yellow card, and he was waved off the pitch by Toon winger Jacob Murphy in comical fashion.
But the incident came from Saint-Maximin at his scintillating best. He was running with purpose, committing players and driving into dangerous areas.
This is the Maxi that we have missed. Hopefully this is a turning point in his season, and we can begin to see more of the player who carried the club on his back in recent years.