McKay pinpoints a Te Awamutu trial win in April as a turning point for Barcelo, who has since gone on to push subsequent Great Northern Foal Stakes winner Ichiban to a nose at Te Rapa before placings at Te Rapa and Hastings.
"I didn't really rate him that highly, but then he won that trial pretty easily and came out and just got beaten by a pretty good one of Rogersons' and I started to change my tune," McKay said.
"He was probably beaten by a half-decent horse [Honey Rider] at Hastings last start, but I was a bit disappointed.
"I made up my mind then not to go to Auckland [for the Foal Stakes] and to back off him and wait for a late 2-year-old race with him now and hopefully he can carry on as a 3-year-old."
Freshened since that second to subsequent Castletown Stakes runner-up Honey Rider at Hastings in May, Barcelo has prepared well for his Ruakaka assignment this weekend to the point where McKay is unsure where his potential ends.
He would love to see Barcelo emulate his Hawke's Bay Guineas-winning stablemate Amarula, who won the same Ruakaka race last year.
"He could be a horse that just keeps improving," McKay said.
"He's probably not in Amarula's class, but we just don't know how much improvement there is in him. I only rated Antonio Lombardo as our third-best 2-year-old of his year but he ended up being our best 2-year-old and going on and doing the job well at three.
"Barcelo has got that will to be a racehorse so hopefully he might be able to make it."
* Awapuni trainer Lisa Latta has her fingers crossed for a better performance from Our Gazza on his home track today.
She said the gelding had been suffering from back problems, but he has responded well to treatment ahead of the Midwest Disposals Handicap.
"His work has been good and we're hoping for an improved performance."
As the winner of eight races on rain-affected ground, Our Gazza will relish the track conditions today.
* Former champion New Zealand trainer Mark Walker has his fingers crossed for track conditions at Kranji to suit his in-form Singapore Derby hope Rockfast tomorrow.
"All he needs is a bit of rain to get the sting out of the ground," he said.
The Te Akau-raced 4-year-old is at the top of his game having won his two lead-up races in impressive fashion.
Meanwhile, fellow Kiwi expatriate Laurie Laxon believes there's a sense of timing about his New Zealand-bred Derby hopes Affleck (Battle Paint) and Mr Spielberg (Pentire).
"They're both very well and have come through their last races in great order," he said.
"They have come right at the right time. My season is coming along too, but sometimes it's not all about the wins - the placings and winning the big races still financially make for good years."
