The Blues, who started their push for a seventh straight title by beating Manchester City 2-1 on the opening Friday, could not have been more excited by the bow of Carpenter, their big signing from Lyonnes who was player of the match.
It even made up for their disappointment at not seeing the return of Sam Kerr, left on the bench by coach Sonia Bompastor, who felt it was too pressurised a match to plunge the Matildas' captain back into the fray for the first time in 20 months.
As for Carpenter's debut, though, she was wholly effusive.
"I know Ellie by heart, and I'm not really surprised about her debut. She's a great player and has brought an immediate impact on the performance and on the result," said Bompastor.
"Having the opportunity to bring players with her quality into Chelsea is always something really positive, and we are really proud to have her in our squad."
Arsenal feel the same about their new Canadian striker, Olivia Smith, the first million-pound player in the women's game, who opened up her Arsenal career with a quite dazzling individual strike in their 4-1 over ambitious WSL newcomers London City Lionesses.
The promoted visitors had the temerity to take the lead at the Emirates Stadium on Saturday, before European champions Arsenal asserted WSL order against the newbies, with Steph Catley secure at the back and Caitlin Foord lively when she came on for the last half-hour. Kyra Cooney-Cross was left on the bench.
But it proved a tough debut for the Lionesses' 30-year-old WSL stalwart defender Alanna Kennedy, who had previously been at Spurs and Manchester City, as she was beaten to the punch for Arsenal's second goal when Chloe Kelly nipped ahead of her to latch on to Alessia Russo's cross.
A tough debut too for another Matildas' centurion Emily van Egmond, newly signed by Leicester City as she suffered a 4-0 defeat at Manchester United on Sunday with United's new French signing Melvine Malard scoring twice.
Midfielder Clare Wheeler came on in the second-half for Everton in the Merseyside derby at Liverpool, helping them to a memorable 4-1 victory at Anfield which featured a hat-trick on debut from their summer signing, much-touted Spanish youngster Ornella Vignola.
A Spurs side featuring Clare Hunt and sub Charli Grant earned a late 1-0 win over Katrina Gorry-captained West Ham United thanks to a Beth England penalty, while Dario Vidosic's Brighton & Hove Albion, who had Charlie Rule in their ranks, opened up with a goalless draw against Aston Villa.
