Another big right hook landed followed up by a monstrous left hand that left Winters stumbling backwards, but on his way down Parker delivered one final right hand.
Winters got back to his feet but the referee quickly waved it off with the American nowhere near able to continue the fight.
"I want to keep busy. Hopefully with 2 more fights this year," Parker said after the fight.
"I want to fight Chisora, Whyte again. Anyone in the top 10."
- More to come
Parker confident going in to fight
Parker, who tipped the scales at 111.54kg, has a 15kg weight advantage over the American, who weighed in at 96.54kg.
The pair were weighed under blazing Texas sunshine on the outdoor stage in front of the fight venue - the Dallas Cowboys football team's new indoor training facility.
And the former WBO heavyweight champion plans on bringing a different sort of heat tomorrow as he attempts to reach the upper echelon of the division again a week after Fury used his greater size to near perfection to demolish former WBC title holder Deontay Wilder in Las Vegas.
It's clear Parker doesn't expect the scheduled 10-round fight against Winters, a 39-year-old former cruiserweight who goes by the ring name "Bald Eagle", to go the distance.
The Kiwi-Samoan, as heavy as he has been for a fight since his points win against Hughie Fury in September 2017, is planning on dominating the middle of the ring and walking Winters backwards.
"It is a big weight difference and I think I have to use that weight to my advantage," Parker said afterwards.
"Most of my fights I've boxed and moved. I'm not going to say I'll do what Fury did because he did a great job and executed the plan, but I have to show more authority in there.
"It's good weight, too."
Parker looked strong and trim in front of about 500 people, many of whom had gathered for the Mikey Garcia v Jessie Vargas main event weigh in. Winters also looked trim after taking off a t-shirt with the inscription "Faith got me living risky". Parker's t-shirt featured a stylised spider, a play on the spider bite which forced him to pull out of his bout against Dereck Chisora last year.
His physical shape suggests he is taking seriously his vow to take every opportunity as he reaches the final third of his professional career. The 28-year-old has said he will only fight for another three or four more years.
The day before he was taken on a tour of the impressive Cowboys headquarters owned by Jerry Jones who bought the franchise for $US150 million in 1989 and has seen it grow to be worth $US5.5 billion now. If there's a lesson in that it may be the value of making wise investments and Parker has done the same in terms of his training, eating and mental preparations.
"If I'm not in good shape now then…" he added in agreement before re-stating his goal for an authorative performance against an older and smaller man, albeit one who is tough and can punch equally well with both hands.
"I've won how many fights going the distance, right? It's great to win but when you're boxing on the back foot all the time it's not really interesting to watch," Parker said. "What I need to do in this fight and I've practiced it, is patience, but throwing the shots that mean something.
"In the [Alex] Leapai fight I threw so many punches but they didn't have a lot of power in them because I was trying to be fast instead of strong and powerful. We've been working on sitting down on the punches and hopefully I can show that.
"I feel like if I sit down on my punches and connect I can knock anyone out. None of this box and move – less moving and more punching.
"He's going to try to push me back … but the weight difference, I don't think he'll be very successful in doing that. I can stand my ground. I've usually been the smaller guy – with [Anthony] Joshua, [Alexander] Dimitrenko, [Dillian] Whyte. But with Shawndell Winters – he has dropped down in weight which means he's trained hard but there's a difference between being a cruiserweight coming up to heavyweight and being an actual heavyweight. We'll see what he can do."
Winters, who boxed about 50 times as an amateur and has a 13-2 professional record, believes he can win and is likely to swing from the start. It may be over quickly.