JOIN USWawrinka needed just one game to complete victory, breaking the former world number one's serve after bad light halted play on Sunday with the score stranded at 4-6, 6-4, 6-7, 6-4, 5-3.
The world number 19 Swiss, who went down to Bernard Tomic in the opening rubber and had struggled on the grass courts at Sydney Golf Club, had also taken pain-killing injections for a foot injury before his fighting win over Hewitt.
Wawrinka teamed up with Federer in a narrow loss in the doubles on Saturday and was delighted to play a decisive part in the 3-2 victory after his more illustrious team-mate won both his singles rubbers against Hewitt and Tomic.
“It's amazing to be in the same team but for sure in Switzerland it is never easy because it doesn't matter what I am going to do or which ranking I am going to have because it's never going to be enough for Swiss people because they always look to Roger -- but that's okay,” Wawrinka said.
Hewitt's loss condemned Australia to their fourth straight defeat in the World Group play-offs.