New Chelsea signing Alyssa Thompson scored her first goal for the Blues.
The 20-year-old US international moved to London from Angel City in September for a reported fee of around STG1 million pounds ($A2 million) on a five-year contract.
France winger Sandy Baltimore and Johanna Rytting Kaneryd put Chelsea in command with a goal apiece less than 10 minutes apart late in the first half at Stamford Bridge.
Baltimore converted a penalty and Rytting Kaneryd doubled the advantage with a looping header.
Thompson added the third after the break from close range and Erin Cuthbert also scored.
Matildas skipper Sam Kerr was initially listed as the scorer before Cuthbert was credited with the goal.
In the new format, the 18-team league phase ends in December. Teams that finish first to fourth in the standings advance directly to the quarter-finals. Those ranked Nos.5 to 12 go to a knockout playoff round. The bottom six teams are eliminated.
In Rome, Barcelona continued their impressive start to the season with a convincing 4-0 win at Roma.
The Catalan outfit, who boast a 100 per cent record after seven games in Liga F, were again on song as Aitana Bonmati and her teammates impressively followed up last week's 7-1 thrashing of Bayern Munich in the league phase.
Esmee Brugts set them on their way after just two minutes at the Stadio Tre Fontane with further goals coming from Kika Nazareth, Alexia Putellas - who scored a penalty after earlier missing from the spot - and Caroline Graham Hansen.
There were two notable accomplishments as record eight-time winners Lyon maintained their winning start with an impressive 3-0 win over Austrian side St Polten at the Groupama Stadium.
United States international Lily Yohannes became their youngest goalscorer in the competition, at 18 years and 125 days, when she completed victory with a spectacular long-range lob from just beyond the centre circle.
That came after Ada Hegerberg, the Champions League's most prolific goalscorer, had extended her own competition record with a 67th goal in her 77th appearance. Jule Brand was also on target for the French side with a first-half header.
Janina Minge scored a winning penalty deep into stoppage time as Wolfsburg snatched a 2-1 victory at Valerenga.
The Norwegians produced a spirited showing and responded to Lineth Beerrensteyn's opener with a header from Sara Horte on the hour.
They looked like holding on until a foul by Naina Inauen allowed Minge the chance to settle the contest with the final kick in the eighth added minute.
Leuven produced a late fightback to beat Twente 2-1. Jaimy Ravensbergen put the Dutch side 1-0 up at half-time but Linde Veefkind levelled from the spot after 82 minutes and Sara Pusztai won it in stoppage time.
with AP
