In women's actions, top seed Simona Halep took sweet revenge on her opponent from last year's French Open defeat, trouncing American teenager Amanda Anisimova 6-0, 6-1 to progress.
But Wu was reluctant to highlight her own performance.
The 33-year-old had scored 45 goals in 68 games and won two A-league championships since he joined the Sky Blues in August 2018.
"Adam has had an unbelievable couple of years with the club and has had a huge influence on our squad," he said.
FC Barcelona coach Ronald Koeman was left frustrated as the club failed to complete deals to bring central defender Alex Garcia and forward Memphis Depay to the club from Manchester City and Olympique Lyon respectively.
Colombia will host Venezuela in Barranquilla on October 9 before facing Chile in Santiago four days later in the opening fixtures of the South American zone qualifiers.
Argentina will host Ecuador at La Bombonera in Buenos Aires on October 8 before a clash with Bolivia in La Paz five days later.
Next up for Halep is another 19-year-old youngster, Iga Swiatek of Poland, whom Halep defeated in the round of 16 here last year.
Union gained momentum but missed the chance to extend the lead at the half-hour mark after Nico Schlotterbeck pulled wide from tight angle.
The 2018 champion lost to Anisimova in the quarterfinals in Paris last year, but this time the Romanian needed only 54 minutes to complete a convincing victory.
TEHRAN, Oct. 3 (Xinhua) -- The Asian Football Confederation (AFC) on Saturday banned Iran's Persepolis forward Isa Alkasir from any soccer activities for six months.