Carpenter, a two-time winner of the competition with Lyon, set up two goals in a 5-2 third qualifying round first-leg win over Real Sociedad for the London club.
That leaves Carpenter well placed to join Manchester City's Mary Fowler and Arsenal trio Cooney-Cross, Steph Catley and Caitlin Foord, whose sides enjoyed direct entry to the group stage after finishing in the Women's Super League top-two places.
However, fellow Matildas Hayley Raso and Jessica Rankin are less likely to make it after their Eintracht Frankfurt team were held 1-1 at home to Paris St Germain. Both began on the bench, with Raso coming on after 66 minutes.
Cooney-Cross returned to her best following an extended absence, scoring a screamer in Arsenal's final pre-season match.
The midfielder went more than five months without playing, having spent the time with her mother after she was diagnosed with terminal Stage 4 bile duct cancer.
Jessica Cooney died on July 10.
Cooney-Cross, making her second appearance since returning, was subbed on at halftime as Arsenal defeated Women's Super League side Charlton Athletic 5-1.
The 67-time international scored Arsenal's third goal, triggering emotional scenes as teammates flocked to her to celebrate.
"That was magic. It was an unbelievable strike," Arsenal coach Renée Slegers said.
"It was also a very special moment for her, so I'm really happy for Kyra."
Matildas teammate Emily van Egmond assisted the Addicks' goal, while compatriots Leah Davidson and Grace Johnston played the second half.
Chelsea's Spanish visitors had stunned them with a seventh-minute opener at Kingsmeadow, but the hosts' superior quality told, with $A1.6 million summer signing Melvine Malard scoring twice on debut.
The French international's second came from a pinpoint cross by Carpenter, who also provided the assist for Chelsea's fourth goal, scored by England's Lauren James, with some fine build-up play.
The second legs are on September 2 (local time).
Matildas Teagan Micah (Lyon) and Wini Heatley (Roma) are also pre-qualified into the group-stage draw, which will be made on September 4.
