Having won three qualifying ties, including a triumph over former world No.38 Donald Young, Baker will take on Czech Lukas Rosol, who beat Rafa Nadal at Wimbledon last year.
Baker trained with Murray in Miami in December, and said: "He is one of the best three in the world, to see what he does on a daily basis has been great.
"Just hitting balls with him is so eye-opening. At times I will come off the court and say I just cannot understand how he has got that good."
After this morning's first session, Novak Djokovic got his bid to win a third-straight Aussie Open title started with a 6-2, 6-4, 7-5 victory over Paul-Henri Mathieu. "It's amazing to be back and thank you all for coming and supporting," he said.
Meanwhile, British No.1 Heather Watson was forced to battle for her second-round spot against Alexandra Cadantu, winning 2-6, 6-3, 6-2.