But a sunburnt Murray needed less than an hour to record a straight sets victory over Kohlschreiber to level the tie.
Murray, 22, won eight of the last nine games to beat Kohlschreiber and set up the mixed doubles decider.
"I practised yesterday (Tuesday) with my shirt off and I got so, so burnt," said Murray, who misjudged the Perth sun.
Murray and Kohlschreiber had never met before but the world number four soon asserted himself by grabbing a break of serve in just the fourth game before winning his next service to love and race into a 4-1 lead.
However, the Scot was pegged back and was broken in the seventh game after dumping a forehand into the net, but he responded to the challenge in emphatic style to claim the first set.
Murray won his next service to love and then won the set on Kohlschreiber's serve with his second set point.
A whirlwind second was then quickly in Murray's keeping as he took just six minutes to go 3-0 up.
That virtually ended Kohlschreiber's resistance as Murray took the tie into a lively mixed doubles.
"I started serving really well with the new balls and then as the first set progressed I started missing a lot of first serves into the net," said Murray.
"I haven't played a match for five or six weeks so it's probably just that. But the Wilson balls are quick and then they do slow down a lot so it does take a bit to get used to.
"It's just little adjustments."
That doubles clash saw the GB pair race into a 5-0 lead after just 14 minutes, and with Robson taking a lead role they powered to the win.
Robson has now lost both her singles matches at the Burswood Dome, but felt she improved on her first-up loss to Yaroslava Shvedova on Monday.
"I made a few more volleys than on Monday so it was more impressive," said the 15-year-old.
"I can still improve on everything, but the match was a lot better than Monday.
"I had chances in the first set, but she just played better in the end."
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