Kenny Knox sank a five-foot par putt on the 18th hole to defeat Gil Morgan by one stroke yesterday in the $500,000 Hardee's Golf Classic in Coal Valley, Ill.

Knox, picking up the PGA Tour event's $90,000 top prize, shot 4-under-par 66 in the final round for a 72-hole total of 15-under 265. Morgan, who began the day with a one-stroke lead, had 68 for 266. Mark McCumber, winner of last week's Anheuser-Busch Classic, took third at 267 after a final-round 67.

Another shot back was Scott Hoch, 1980 and '84 winner of the Hardee's, then known as the Quad Cities Open. He shot 65 to end three shots off the pace.

Senior PGA Tour:

Bruce Crampton ran away with his second consecutive title at the $250,000 Syracuse (N.Y.) Senior Classic, bettering the course record with 19-under-par 197 for 54 holes and securing a six-stroke victory over Chi Chi Rodriguez.

Crampton's score, 65-67-65, which earned him $37,500, was the seniors' best this season.

LPGA:

Defending champion Jane Geddes made a four-foot birdie putt on the 18th hole at the $300,000 Boston Five Classic in Danvers, Mass., for her fifth victory of the year.

Geddes, who next will defend her U.S. Women's Open title, fired a bogey-free round of 67 for a 277 total that edged Donna White and Jody Rosenthal by one shot.

With the $45,000 first prize, Geddes becomes the 1987 tour's leading money winner, with $346,947. Betsy King, who tied for fourth, two shots back, dropped to No. 2 with $328,856.

Virginia Open:

Richmond pro Tim White rallied at his home Brandermill Country Club's back nine for a 2-under-par 70, a 72-hole total of 285 and a one-shot victory over Alexandria's Wheeler Stewart in the $50,000 Signet State Open.

The top prize of $5,400 was the biggest ever for White, 28, an assistant pro who started the day three shots behind two-time state amateur champion Tom McKnight of Galax and five behind Stewart, the pro at Belle Haven.

Stewart put his drive on the final hole into the water, took a 76 and settled for $3,600. McKnight three-putted the final green for 75 -- 287 and third place. Defending champion Woody FitzHugh of Great Falls shot 76 and tied for sixth at 291.