The Northern Irishman, playing his last event before The Ryder Cup in October, looked to be in great form as he birdied four of his first five holes at Diamond Country Club.
He then responded to a bogey at the 17th with another gain before parring every hole on the way in for a four under 68 and seven under total.
"It's very much the old cliché of a game of two halves, this golf course," said McDowell - who can close the gap to Martin Kaymer at the top of The Race to Dubai this week.
"This front nine's quite tricky and you've got to drive the ball unbelievably well to have any chance of making birdies. On the back nine it's a lot more three woods and hybrids off the tees which offers you a few more opportunities and I think the greens are a little flatter as well.
"I think I'm two over par for the front nine and nine under par for the back nine overall so I certainly know where I need to make up some shots on the weekend."
Lara joined him after a mixed round of four birdies and three bogeys in a 71.
The former UBS Hong Open winner is down at 130th on The Race to Dubai and looking for a good performance this week to move into the top 115 that retain their playing cards at the end of the season.
“Everything has changed, now I’m 33 and my mind is not the same as before,” said Lara. “And we have new grooves, new courses - The Tour is changing every year.
“I still feel young in myself, but there are many young Spanish guys coming up now and already have their cards. So I need to fight this year and that’s what I’m doing.”
England's Danny Willett is a shot further back on six under after a second consecutive 69, along with Swede Pelle Edberg and local amateur Matthias Schwab, both of whom had two holes remaining.
Overnight leader George Coetzee started with a birdie at the first to reach eight under, but a double bogey at the second saw the South African six under after five holes.