The Irish were booed off the field at the Aviva Stadium after the loss to the Swedes, which leaves their hopes of qualifying for next summer's World Cup in Brazil hanging by a thread.
However, the former Tottenham Hotspur hitman, who netted his 60th international goal in the defeat, has said that the veteran Italian has retained the support of the dressing room, despite losing the fans.
He told reporters: "As professionals, as far as we are concerned he is the manager and we are going to give him 100% backing.
"We have a game on Tuesday [against Austria] and if we don't get anything out of it, it's finito, it's as simple as that.
"If they can't get themselves up for these games knowing how important the game is, then there's a serious problem."
The loss has left Ireland in fourth place in Group C, level on points with Austria above them.