Graeme McDowell surged into contention for the Corales Puntacana Resort and Club Championship after a brilliant second round in the Dominican Republic.

McDowell bounced back from an opening 73 to fire eight birdies in a flawless 64 on Friday to lie three shots off the lead held by Korea's Sungjae Im.

Im carded a second successive 67 to reach 10 under par, a shot ahead of Ireland's Paul Dunne, Australia's Aaron Baddeley and the American pair of Jonathan Byrd and George McNeill.

McDowell's 64 was his lowest on the PGA Tour in relation to par since an eight-under 63 at the Mayakoba Golf Classic in 2015, an event he went on to win.

The former US Open champion had double-bogeyed his final hole on Thursday and told the PGA Tour website: "My iron play wasn't good enough and (the double bogey) made sure that I had something to work on this morning before I went on the golf course.

"So I was able to just focus on fixing that left shot that I had. I hit it several times yesterday and it got me in trouble of couple of times. I kind of needed a rescue today."

McDowell is exempt into this year's US Open at Pebble Beach, where he won in 2010, but has yet to earn a spot in The Open Championship at his home club of Royal Portrush.

Overnight joint leader Matt Jones is alongside McDowell on seven under after recovering from a quintuple-bogey nine on his first hole of the day to shoot 71.

Former Dallas Cowboys quarterback Tony Romo added a second round of 80 to his opening 79 to finish 15 over par