Four-time major winner McIlroy beat American Scott Stallings 3&1 with a new putter and new driver.
“It was a good first outing for both those clubs,” McIlroy said. “They performed pretty well.”
The 2015 Match Play winner from Northern Ireland said the event helps prepare him for stroke-play challenges to come.
“There’s a ton of golf left this season but to get a bit of match play in our lives is good, and to get under pressure,” McIlroy said.
US 20th seed Keegan Bradley, 4-down after 13, won four of the last five holes, his six-foot birdie putt taking 18 to tie countryman Denny McCarthy in McIlroy’s group.
Zalatoris dropped the last three holes to fall 3&2 to 56th-seeded compatriot Andrew Putnam.
Scott, the 2013 Masters champion, last won a PGA title in 2020 at Riviera.
“I haven’t won anything much in a long time,” he said. “A win feels satisfying.”
South Korean 16th seed Im Sung-jae beat US 58th seed Maverick McNealy 8&6, matching the most lopsided group win at Austin.
US 61st seed J.J. Spaun never trailed in upsetting England’s 11th-seeded Matt Fitzpatrick 5&3. Spaun won four of the last five holes from the reigning US Open champion with three birdies and an eagle hole-out from 107 yards at the par-4 13th.
