Opener Marcus Harris is expected to be the man battling to keep his spot, after failing to turn a run of starts into his first career century this summer.
While Head is expected to return at No. 5 after averaging 62 this summer before contracting the virus, he admitted he was uncertain on whether he'd get his spot back.
"We'll wait and see," Head said. "I think he [Khawaja] played beautifully. We spoke about that going into the series when it was questioned who would be in that side.
"We felt like both of us were in great touch. We know he is versatile and the way he can play. If there was a spot open in the side that he would take that opportunity.
"He's taken it with both hands, he's been amazing. There's going to be some tough decisions. Those conversations haven't been had yet."
Head has been a vocal supporter of Harris this summer, constantly referring to the way his fellow left-hander is lining the ball up. Selectors have also been clear they want to put their faith in Harris and give him a long run, with David Warner having continually shuffled through partners during his career.
Khawaja is, however, one of the 13 men to have opened with Warner, averaging 95.60 in his seven innings at the top of the order. Head said Harris was not showing signs of nerves since Khawaja piled on the runs at the SCG, remaining an upbeat member of the playing group.
"He hasn't changed and I think that's the beauty of the whole squad. We celebrate each other's success," he said. "We're currently 3-0 up. We played a great week again. He's been amazing.
"He's playing for Australia, doing a job. He was a fantastic in Melbourne, played a huge role in us winning the game. He will be disappointed he didn't get runs in this game and had a great opportunity. I felt like he batted and line the ball up beautifully well.
"He batted beautifully at the start and set really the platform with him and Davey as a partnership."