Keane, who spent the opening 45 minutes on the bench, came on at the start of the second half and converted a 68th-minute penalty after a Calum Woods own goal had put Celtic ahead.
"The most important thing was getting the win - they certainly made it difficult for us," the Irishman, who denied he was disappointed to start the game on the bench, told Sky Sports News.
"It's about the team and about the squad and the lads who came in were superb."
Celtic manager Tony Mowbray hailed the contribution of his January recruit from Tottenham, saying: "He adds real quality, real class.
"His quality in the final third made the difference."
Mowbray added: "I thought we controlled the game pretty well, although it was disappointing to lose the goals."