Billy Glasson birdied the last three holes in the gathering darkness of early evening for an eight-under-par 62 and took the first-round lead yesterday in the rich Panasonic Las Vegas Invitational golf tournament.

Glasson was the last man off the tee at the Tropicana Country Club course and completed play moments before nightfall. His late burst of birdies placed him, depending on how it's figured, two shots in front of Tom Watson or three in front of Scott Hoch and rookies Paul Azinger and Phil Blackmar.

The confusing situation arises from the format for this five-day, 90-hole event that offers a total of $1,042,000 in prize money. The pros are required to play one round on each of three desert courses -- the Tropicana, Desert Inn and host Las Vegas Country Club courses -- before the field is cut for the final two rounds at the Las Vegas course.

The courses have different pars -- 70 at Tropicana (where Glasson, Blackmar, Azinger and Hoch played their first rounds), 71 at Las Vegas and 72 at Desert Inn, where Watson played his first round. On a numerical basis, Blackmar, Azinger and Hoch, with five-under- par 65s, were tied for second, three shots back. In relation to par, Watson, with a six-under-par 66, was second, two shots back.

The situation will be resolved only after players have completed one round over each of the courses.