Cook, who took gold in Sydney 2000 and bronze in Atlanta 1996 with a different partner, helped her new team mate Nicole Sanderson battle nerves and an imposing Chinese defence to win in the second preliminary round game of the Athens Olympics.
"She was a little bit tight," Cook said of her partner, who admitted her "heart was still beating hard" after the match that reached a tie-break after 17th-ranked Lu Wang and Whenhui You showed brilliant defence play to take the second set.
Cook, who has delayed shoulder surgery until after the Olympics, said it was good to have a challenge in the early rounds -- "but I don't like them that tough!"
All teams playing in the morning session were forced into tie-break sets as they contested the second of three preliminary round matches.
Bulgaria's sister duo of Tzvetelina and Petia Yanchulova upset 2003 world champions Stephanie Pohl and Okka Rau of German in three sets 18-21, 21-19, 15-13.
Norway's Vegard Hoidalen and Jorre Kjemperud, who were upset by Sweden in their opening match, found their rhythm after dropping the first set and beat Ramon Hernandez and Raul Papaleo of Puerto Rico 18-21, 21-19, 15-10.
Switzerland's Patrick Heuscher and Stefan Kobel clinched a place in the 16-team elimination with a 16-21, 22-20, 15-9 victory over Australia's Julien Prosser and Mark Williams.
Each team plays three preliminary matches. The top two from each pool advance to the next round of competition along with the top four third-place finishers.
