Sydney FC secured the A-League Premiers Plate after Saturday's 1-1 draw between Wellington Phoenix and Adelaide United ensured that the defending champions would finish top of the table at the end of the regular season.
Sydney, who will have top seeding in the championship playoffs for the third time in the last four campaigns, needed only one point to secure the trophy but lost to Newcastle Jets on Tuesday.
"An incredible night for our club and a remarkable achievement by a special group of players and coaches," Sydney FC chairman Scott Barlow said on the club's website.
"Tonight we won our fourth Premiers Plate, a new record for an A-League club, and combined with our four Championship titles, adds to our club's long history of success.
"The last few months have certainly had its challenges and I'd like to thank everyone at the club, including our passionate fans and Members, for their patience, professionalism and commitment to Sydney FC. This title belongs to all of you."
The draw lifted Wellington into second place above Melbourne City on goal difference, but they will not be able to catch Steve Corica's men, who have an 11-point cushion and four games in the regular season remaining.
Wellington and Melbourne are on 40 with three games left.
Wellington had the chance to clinch a last-gasp win and make Sydney wait but had a penalty from substitute Ulises Davila saved by Adelaide goalkeeper Paul Izzo with minutes remaining on the clock for the end of regulation time.
"Our congratulations go out to Sydney FC for claiming their fourth ... Premiers Plate," Football Federation Australia chairman Chris Nikou said in a statement.