Sunderland manager Simon Grayson made several changes before the start of the second half, including bringing on the18-year-old Nigerian striker, who had trained with the first team at their training camp in Austria.
With the Black Cats trailing 2-1, Maja equalized when he slid in to send the ball over the line after picking up Khazri's pass in the 77th minute.
On 86 minutes, he made it 3-2 and put Sunderland in front for the first time in the game after Murphy failed to stop his well-struck volley.
Josh Maja was invited by the Nigerian Federation to train with the Super Eagles during their get-together in London but didn't turn up due to club duties.