Mark O'Meara fired a 5-under-par 67 to take a two-stroke lead after the second round of the PGA's 90-hole Las Vegas Invitational. O'Meara has a 13-under 131 total. Tim Simpson and Duffy Waldorf are tied for second at 133. Loren Roberts, Robert Wrenn, Bob Tway, John Cook and Emlyn Aubrey are tied for fourth at 134. And in Scottsdale, Ariz., Jim Stuart took a two-hole lead midway through the back nine and went on to defeat Mark Sollenberger 1 up in the U.S. Mid-Amateur Championship. It was Stuart's first national championship and qualified him for the 1991 Masters.