The Gunners sealed their place in the qualifying first-round final with a 3-0 win against Linkoping in Sweden, with Foord scoring the vital breakthrough goal in the second half on Wednesday with a header.
Foord carried on where she left off in a fine World Cup, during which she largely carried Australia's attack in the absence of the injured Sam Kerr, scoring once and assisting on two other goals during the tournament.
This season, she again promises to be a key figure for English Women's Super League contenders Arsenal, after signing a new deal with the club in June following her 11 goals and nine assists for them last season.
Her first major contribution since penning the deal was to score the key goal that settled Arsenal nerves after captain Kim Little had seen her early penalty saved and Lotte Wubben-Moy's first-half header hit the post.
The last time they were on the same pitch was three weeks ago when Russo's late goal sealed England's 3-1 win over the Matildas in the World Cup semi-final in Sydney.
Former European champs Arsenal will on Saturday next face Paris FC, who beat Ukraine side Kryvbas 4-0 later on Wednesday, for a place in the two-legged second qualifying round. The winner of that match would then qualify for the group stages of the League.
Elsewhere, Arsenal's former Australian manager Joe Montemurro presided over Juventus's 6-0 win against Kazakh side Okzhetpes to set up a final in their mini-group in Germany with hosts Frankfurt, the former champions who beat Czech side Slovacko 1-0.
Celtic registered their first win in a Champions League tie as Kelly Clark's second-half goal earned them a 1-0 win against Brondby in Oslo.