Giteau's poor kicking display against Scotland included a missed conversion during the game's final nerve-tingling seconds. It meant the Wallabies suffered a 9-8 defeat - their first loss to Scotland since 1982 - and provided the low point of their current European tour.
But Gatland, whose team are next up for Giteau and company at the Millennium Stadium on Saturday, does not expect a repeat.
"Matt Giteau is a real competitor," said Gatland. "Champion players don't tend to back up with poor performances twice in a row, and we are all expecting Matt to play really well on Saturday."
He added: "Knowing the Australian attitude - it doesn't matter whether it is rugby union, cricket, rugby league, whatever - when their backs are to the wall, they tend to respond.
"We expect them to play with a lot of passion.
"It doesn't matter what sport you play against Australia, if you chalk up a victory it means a lot."
Gatland has made a solitary change from the team that beat Argentina 33-16 last weekend, recalling Sale Sharks scrum-half Dwayne Peel instead of Gareth Cooper.
Gatland's selection means that nine players - James Hook, Leigh Halfpenny, Jamie Roberts, Gethin Jenkins, Paul James, Alun-Wyn Jones, Luke Charteris, Andy Powell and skipper Ryan Jones - will have started all four of Wales' autumn Tests.
There are also nine survivors from the starting line-up that accounted for Australia 21-18 a year ago, and the bookmakers have installed Wales as favourites this time around.