The 54-year-old American was one of only two players to make par in Friday’s second round and he did so in style, although it could have been an equal course record had he managed to sink a 10-yard putt for a birdie on the 18th.
"I played aggressively today and had some great putts go in," said Hallberg. "I missed some putts, probably six, seven feet today and started to get nervous a bit at the end.
“I haven't been nervous in a while, but it's nice to get to that point where you can get that nervous. I had that putt on the last hole and I wanted that real bad."
The only other man to make par on Friday was Fred Couples, who managed a two-under 68.
Hallberg, who had a dreadful front nine in Thursday’s first round, now has the biggest lead going into the third day of this event.