The 29-year-old midfielder joined the Reds with a reported fee of 20 million pounds (about 25.8 million US dollars) for four years to become the club's second signing of the summer transfer window, following Kostas Tsimikas in August.
In the women's draw, US Open quarterfinalist Elise Mertens of Belgium disposed of Chinese Taipei's Hsieh Su-Wei 6-3, 6-1.
Koeman had expressed an interest in signing Dutch international Memphis Depay from French side Lyon, but in a TV interview on late on Tuesday, he explained that Barca's economic situation was complicating the deal.
In Group D, Al-Nassr FC of Saudi Arabia continued their charge towards the round of 16 with a 2-0 win over Iran's Sepahan thanks to a brace from Abderazzaq Hamdallah.
Five minutes later, the crossbar denied Dortmund a greater lead before the break, as Jadon Sancho's header bounced off the woodwork.
The new season is said to be Lucien Favre's last chance to turn things around after the side failed to overtake their high-spending Bavarian rivals in the past two years.
According to Polish media, the English side bought the Poland international for about four million euros. On Wednesday, the 22-year-old passed a medical and signed a four-year contract which is valid to June 2024.
Along with fellow new boy Allan, the Colombian was lively throughout and the Toffees fully deserved their win, with Dominic Calvert-Lewin's thumping header proving decisive.
In the 80th minute, with the assistance of Jean Evrard Kouassi, Eddy Gnahore slotted home with a goal for Zall to narrow the gap to 2-1 and had to settle with the score.
After suffering five defeats consecutively, Qingdao had no chance of being among the top eight in the next league session, although three games of the first session remain on the schedule.
Pakhtakor goalkeeper Suyonov was sent off in the 65th minute and Sanzar Kuvvatov was brought on to take his place. But almost instantly, the Uzbek side rallied at the other end of the pitch and replied with a goal, as substitute striker Eren Derdiyok blasted in the rebound after Dragan Ceran's initial effort was saved.