The triple major winner found the Greg Norman-designed Earth layout a fearsome opponent in practice earlier this week and he was delighted to tame the course once the action started for real.
"I shot 67 doing handstands today," Harrington told reporters on an unusually overcast day in Dubai. "Sometimes you do that when your expectations are low.
"Today I wasn't very confident going into the tournament so anything was going to keep me happy out there and I'm pleased with the score."
The day started in the Emirate with a tropical downpour first thing in the morning and it was soon raining birdies for Harrington as he picked up six in his round plus a solitary bogey.
"It could have been numerous shots better," said the 41-year-old Irishman at the European Tour's season-ending tournament. "I missed an awful lot of chances.
"You don't play like that every day and I'm not expecting to play like that for the rest of the week."
Harrington won the Grand Slam of Golf event in Bermuda in October to end a two-year victory drought but has missed the cut for the last two weeks, at the Singapore Open and Hong Kong Open.
"I had the flu all week in Hong Kong," he said. "I played two rounds of golf but the rest of it I spent holed up in bed trying to recover.
"I suffered a bit of a relapse this Tuesday. I still have a bit of a cough so I won't be doing too much practice this week, just taking it easy."
Harrington certainly did not find it easy in practice in Dubai on Tuesday.
"I didn't play very well then," he said. "I found the golf course very difficult and had to hit woods going in to a lot of the par-four holes.
"Maybe I was a bit tired but I found it a real tough course on Tuesday. Going into today I would have taken anything that was under par."
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