Armour, who has had three runner-up finishes during his first year on the Champions Tour, had a one-shot advantage over Mark Calcavecchia and David Frost. Jeff Sluman and John Cook shared fourth place at 65.
Armour had a history of producing low scores on the regular PGA Tour. He established the circuit's all-time 72-hole record with a 26-under 254 total in winning the 2003 Texas Open.
Nick Price, Hal Sutton, Tom Jenkins and David Peoples were tied for sixth at 66 and Bernhard Langer was among those who shot 68. Langer won major championships each of the last two weeks at the Senior British Open and the U.S. Senior Open.
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