I am Invincible has had nine stakes winners in the first two months of the season, including four in a remarkable 24 hours over the weekend, which included Group 1 winners at Randwick and Moonee Valley.
It sees him well on top of the Australian sires' table in terms of winners, prizemoney and stakes winners.
But while the numbers are impressive, it is the diversity of winners he is producing which most pleases Mitchell.
"I think he's proven, with the Gimcrack winner yesterday and Viddora winning a Group 1 as a 6-year-old. That they train on and they are sound horses," he told TDN AusNZ.
"They are good legged horses. We don’t do a lot on their legs. They mostly come out with good conformation, which obviously make for better soundness possibilities because they don’t have to have any surgeries."
"They are good looking and athletic horses and that helps the longevity too."
Mitchell points to no better example of that than the 7-year-old sprinter Voodoo Lad, who is from I Am Invincible's first crop and has had a career-best campaign, including a victory in the G3 Aurie's Star S. in August.
"They are good looking and athletic horses and that helps the longevity too," Arthur Mitchell.
While he was scratched from Friday night's G1 Moir S., it was another of the stallion's progeny, the 6-year-old mare Viddora, who stood up to record her second win at the top level.
The Lloyd Kennewell-trained Viddora has been linked with the final slot in The TAB Everest after her success and Mitchell thinks it would be a deserved invitation, one which would see her join Invincible Star in representing her sire in the $13 million race.
"There are various rumours swirling around. I think she deserves her shot. I would have thought so. If she doesn’t go for that, there's still the (G1) Manikato S. and lots of good racing coming up. I think she deserves her chance. She's a good mare, a very good mare," he said.
Australia's best maiden no more
A day after Viddora's success, Tony McEvoy's filly Oohood shed her tag as Australia's best maiden in the best possible way with a win in the G1 Flight S. becoming the fifth individual Group 1 winner by I Am Invincible.
"I think she deserves her Group 1. She was unlucky in a few at two and again another one that has trained on to win Group 1 at a mile at Randwick. It’s a good effort, a good training effort and she's a good filly," Mitchell said.
The Flight represented the first time I am Invincible has quinellaed a Group 1 race, with Fiesta beaten narrowly. In the four legs of the Darley Princess Series, she finished second three times and won the opening leg, the G2 Silver Shadow S.
Catch Me flies in Gimcrack
Earlier on the Randwick card, another filly by I am Invincible won the opening 2-year-old race of the season, the G3 Gimcrack S.
The Peter and Paul Snowden-trained Catch Me, a $625,000 buy for Yulong Investments at the 2018 Easter Sales, was ultra-impressive winning by two and three quarter lengths.
"He can get a nice filly and get a nice colt, it’s pretty attractive isn't it," - Arthur Mitchell
"She looks smart," Mitchell said. "She was an expensive yearling and don't forget she was sold at Easter, so she hasn’t had the extra prep and a half that the Magic Millions yearlings get."
"They get a fair advantage as 2-year-olds because they get broken in a lot earlier and educated, so to do what she did is a good effort. A good effort by the Snowdens as well."
An eight-time Group winner
The other big winner for I Am Invincible was the wonderfully consistent I Am A Star, who claimed her second G2 Stocks S. at Moonee Valley on Friday night. All four stakes winners over the weekend were either fillies or mares.
"He can get a nice filly and get a nice colt, it’s pretty attractive isn't it," Mitchell said.
And Mitchell feels that with such positive signs about the durability of the breed, the stallion is poised to ascend to even greater heights in the coming seasons, supported by a stronger book of mares.
"Last year and this year he has covered some of the best mares in the land, and they'll get nurtured," he said.
"The number of Group 1 winners that have come through and with young, fast stakes winning mares, he's got to get better. The first four crops are out of pretty basic mares, the stallion did all the upgrading. Let’s hope he can hold his own with the better mares."