Tiger Woods has broken his record haul of birdies for the first 36 holes of any tournament at the WGC-Cadillac Championship.

The 37-year-old leads by two shots at the halfway stage in Miami having carded 17 birdies in his first two rounds.

However, the 14-time Major champion played down breaking his personal record of 16 birdies, stating that it only means he has started well.

"That's a good start," Woods told reporters. "I'm playing well and I made a bunch of putts, but more importantly, I left myself in the right spots to make putts.

"I think that's probably the biggest key is that I left myself where I didn't have that many downwind, downhill, downgrain, downwind putts.

"I kept leaving myself where I could be aggressive. These [greens] are getting baked out fast and they are getting really tough to get close or even hold the green sometimes. It was important to leave my ball in the right spot."

Graeme McDowell is in second place on 11-under par.