The Game Changer rewards the player responsible for the most effective single performance each month, according to the Opta statistics.
In addition to scoring a 16th minute try, Stephenson registered an impressive 12 carries and 45 metres in attack with nine tackles and a turnover in defence.
Stephenson's score was also voted the Aviva Premiership's Try of the Week, an accolade which also came the teenager's way the following week after the home win over Gloucester.
The recognition has been coming thick and fast for the England Under-20 centre, but he admitted that he was not expecting the Gatorade Game Changer Award.
"It was a massive surprise, to be honest," he told SaintsTV. "It's great for me to get the recognition, but the most important thing is that the team is winning. That's all that matters.
"You always try to back yourself, and I've been delighted by how it's gone in the first team. It can go one of two ways - and for me it's luckily gone the right way."
Each of the monthly Game Changer winners will be competing for the Game Changer of the Season Award which is announced in May.
The G-Series Pro products from Gatorade can be ordered online at www.gatoradestore.co.uk
And you can read a full interview with Stephenson in this week's Rugby Paper, available from Sunday, March 9th.
