The Celta captain opened the scoring from Nolito's pass after 15 minutes in an entertaining match which saw Celta play some impressive football.
"Signing for this special club was never in doubt," the striker told the Arsenal website, adding it was "thanks to our fans, my teammates, my family and everybody at this club that I feel like I belong here."
Earlier in the day, women's 200m saw Kong Lingwei win with 23.64s as top favorite Ge failed to finish the race.
Fulham almost had the perfect start when an errant pass from Gabriel allowed Aboubakar Kamara through on goal, but Arsenal keeper Bernd Leno was able to scramble the ball to safety.
Jablonec took the lead for the first time 12 minutes into the second half after the Slovak striker Ivan Schranz tapped in a loose lob from his teammate past the outstretched Dunajska Streda's goalkeeper Martin Jedlicka.
"It's great to play and to be back with my teammates. I return with a victory and a goal, so I am happy. We are getting our feeling back, our way of playing," the 21-year-old Mbappe said after the match.
"The result didn't meet my expectations, I was thinking about 20.50s or so," said Xie.
In the other two games played on Saturday, Tianjin Teda entered the second round with a 2-0 win against Shijiazhuang Ever Bright, Wuhan Zall secured a last 16 round position after defeating Hebei China Fortune 5-4 (tied 1-1 in 90 minutes) after the penalty shootout. Enditem
Luo Chun and Xu Shuangshuang claimed the titles of men's and women's 3,000m steeplechase, team Sichuan swept the gold medals in men's and women's 4X400m relay. Enditem
Five minutes later, Khalid Bawazir equalized for Sharjah as the midfielder received a pass and rifled an effort that flew straight through the hands of the goalkeeper.
Will Schalke 04 and Werder Bremen experience a change around after both fallen giants only narrowly survived a terrible last season?