The Ellis Winsloe-trained 9yr-old left few excuses for his opposition while carrying the top weight of 60kg in scoring his 14th career win in open handicap company over 1200m.
The crushing victory under rider Shaun McKay means Irish Excuse has now won in every season he has started in since his maiden victory as a 3yr-old.
"He's been a great horse who has won 14 now and has never come down in the grades," Winsloe said.
Irish Excuse did it the hard way again on Saturday with Winsloe booking McKay, rather than engaging a claiming apprentice.
That is nothing new for the No Excuse Needed galloper, who won the same race in 2017.
"It was a great ride, as Shaun is a good rider and he was the horse to suit him," Winsloe said.
"I was getting a hard time for not putting a claimer on him, but Sam Collett won on him fresh-up in a similar sort of race. So, we stuck with Shaun and forgot about the apprentice allowance."
McKay praised Winsloe for having Irish Excuse ready to defeat Tabard, who carried 7kg less than him, in the horse's first start since April.
"He has done a terrific job to get the horse fit and for a horse who was carrying 60kg to beat one carrying 53kg, it's a big effort."
Irish Excuse did not begin brilliantly, but was quickly up on the speed for McKay.
The pair stalked Black Label and rider Kylie Williams before Irish Excuse produced his winning run in the straight.
The victory took the veteran sprinter's record to 14 wins and 19 placings from 67 starts, with career earnings of $225,275.
Winsloe produced Nomen Ludi for a creditable fifth in the group 3 Winter Cup later on Saturday.
Southern success on day one of the carnival built later when Riverton trainers Kelvin and Aimee Tyler produced Galway Garry to win the final event.
It was worth the wait for the father and daughter when the 6yr-old bolted in by 13 lengths in rating 72 company over 1800m for rider Kozzi Asano.
The Tylers earlier produced Flying Sardine to score the second group 3 placing of her career with her third placing in the Winter Cup.
