He holds a four-stroke lead, but if Trevor Immelman doesn’t win, you might point to No. 7 as a turning point.

After knocking his approach inside five feet, he badly pulled his birdie putt. It would have given the South African a five-stroke lead at 12 under, what with playing partner Brandt Snedeker making bogey from a greenside bunker – and with a good birdie opportunity awaiting Immelman at No. 8.

Wow, now his lead is only two shots over Steve Flesch ... Immelman just three-putted for bogey at the par-5.

Immelman’s sudden woes with the flat stick is stunning. He ranked T-13 in putting through three rounds, and had made nearly everything he looked at.

Hey, you better bank every shot you can on the first nine, because everybody’s going to make their final charges on the second nine.

Paul Casey became the first casualty among the leaders. He fell hard, too, beginning with a double-bogey at No. 4 and following that with four more bogeys in a row.

Where’s Tiger? Six behind at 5-under.

Exactly where he started. And he just plunked his approach to No. 10 in the right bunker.

So they say the Masters doesn’t start until the back nine on Sunday?

We are about to find out ...