But the striker knew that to make his mark, he had to keep his composure - and it paid off as Toney wreaked havoc with Slovakia's defence following the long throw-in that led to Jude Bellingham's stunning bicycle kick goal before he provided the assist for Harry Kane's winner.
"There was always going to be a big chance in the dying moments and I feel like my presence on the pitch, trying to rough up a few defenders, there's going to be a chance for someone, and I think the three, two, one minute, however many I got, there would have been an opportunity," Toney told reporters on Wednesday.
The wild ending propelled England into the quarter-finals where they face Switzerland on Saturday in Duesseldorf.
Toney, who received a standing ovation from the raucous England fans when he earned the team a free-kick, had 22 touches in his 30 minutes, only six less than Kane who played 105.
The striker credited Michael Caulfield, one of the UK's leading sports psychologists who works with his club Brentford, for helping him deal with his anger.
"He's always talking about controlling your emotions and in that moment yes I'm annoyed, but there's still five minutes of football to play," Toney said. "There's five minutes of football and you've got to play your part.
"It was up to me to kind of put myself in a space, get out of my mood, get on with the game."
Southgate said he knew Toney "had the hump" about the late substitution, but the striker said making up had been easy.
"By winning," Toney joked.
Toney is not alone in being frustrated by lack of playing time in Germany along with Jarrod Bowen, Eberechi Eze, Anthony Gordon, Cole Palmer and Ollie Watkins.
"It's going to be tough for all of us because most of us play week in week out for our clubs," Toney said.
England lost the 2020 European Championship final in a shootout against Italy, which will be partly remembered for the racial abuse suffered by Black players Marcus Rashford, Jadon Sancho and Bukayo Saka after they missed their penalties.
Asked if that would deter him from taking a penalty, Toney said he was a confident person. He has converted 30 of the 32 penalties he has taken in his career.
"If I score, I score. If I miss, I miss," he said. "You have to step up and you have to have the courage to take a penalty. For those who racially abused a player for missing a penalty, more fool them."
Although England have lost only three of their 27 matches against Switzerland and have not tasted defeat since a World Cup qualifier in 1981, Toney expects a stiff challenge from a team who beat Italy 2-0 in the last 16.
"Switzerland are a great team," he said. "They have quality players and they've been playing well this tournament."