The double major winner had led by three strokes after six holes at the Honda Classic on Sunday and appeared on course for his first US PGA Tour win since 2012 before a double bogey at the par four 16th was followed by a bogey at 17.
McIlroy recovered with a birdie at the par five 18th to sneak into a four-way playoff, though he could not stop American Russell Henley from sealing the win.
Rather than frustrate McIlroy, the result identified a small area in which he needed improvement and set to work this week to correct the issue.
"Looking at last week as a whole, definitely a lot of positives to take," said McIlroy. "I was just disappointed with how I played coming down the stretch. It obviously wasn't what I would have liked.
"I had a really good practice session yesterday up in Palm Beach just working on the shot that I struggled with coming down the stretch, which was just that little hold up shot.
"It's a comfortable shot for me. I just didn't execute it well enough on Sunday."
The wobbly finish at Palm Beach Gardens spoiled what had been a period of encouraging play after he failed to record a win on the PGA Tour last year and live up to his number one ranking.
In three starts this season, McIlroy has produced two top 10s and if not for some brief lapses could have found himself back in the US Tour winner's circle.
"The run of form that I've been on, it does, it validates what I've been working on and what I've been trying to do with my golf game," said McIlroy.
"I'm in a really happy place with where everything is at in my swing. Mentally I feel good. My putting feels good; scrambling.
"So all aspects of my game I'm happy with.
"It means when you go out to the golf course, you're confident and you're thinking about shooting low scores.
"You're thinking about getting into contention."
McIlroy said he does not enter every event believing he is going to win though his goal was to put himself in contention to win every week, something he was unable to do last season.
"You're not going to win every event that you play but if you can give yourself at least a chance going into Sunday, then that's all you can really ask of yourself," said McIlroy.
"I don't think it's not realistic to sit here and say, I want to win every tournament I play, because ...history shows it's just not possible.
"But giving yourself a chance and getting yourself into contention is what I expect of myself and everyone knows that I didn't do that enough last year at all.
"I've started this year better because I've been in contention every time that I've teed it up."
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