The Three Lions are guaranteed to qualify from Group G if they beat the Central Americans, who began their campaign in Russian Federation with a 3-0 defeat to Belgium.
Southgate played down the controversial publication of assistant manager Steve Holland's training notes ahead of facing Panama, as well as tempering concerns over the sweltering heat in Nizhny Novgorod and officiating in Russian Federation.
"This morning he followed the exact programme we had planned", Southgate said of Alli. I've had more knocks than a penalty decision given against me. But it made such a foul up of the early games, free-to-air broadcaster SBS stepped in and is now showing every single group game free of charge.
"I'm relaxed. The team came out three days before the first game and I didn't say anything because it's something we can't control".
"Emails were exchanged, and Dan asked for some clarity and we were happy with the responses".
"Even during the second half, when the pace of the game slowed, England were still on top and had all the possession".
England have opted to remain at their base in Repino rather than train in Nizhny Novgorod ahead of the match, and Southgate added that he is prioritising his players' physical preparation over adaptation to the differing climates of the host cities.
Taking also into account that a veteran-heavy Panama team will be facing a young England squad, there is a sense within the Panama camp that something special could happen on Sunday. The front sheet is always the runners and riders in training, and behind that all the changes we'll make in the session. Because we had the referees meeting and if we do put that forward to them and he doesn't agree, he can show us the yellow.
"The heat is of course different in different parts of the country and we just have to adapt to that".
The England manager gave mixed messages about the much-publicized gaffe by assistant coach Steve Holland, whose training notes, photographed by the media, apparently revealed England's starting line-up.
The night may have ended in 95th minute disappointment for Janne Andersson's side but his gutsy team surely carried not only a nation with them during a pulsating match against the world champions but an army of fans across the world who appreciate the artisan work of an underdog. "We have a certain stability and an organised team". That's been a theme right the way throughout.
Stones was one of the standout performers in the Three Lions' opening Group G encounter against Tunisia, and Southgate will hope he can maintain that form as the opponents will inevitably get tougher.