During a long conversation at Boro's training ground on Thursday afternoon, Southgate was his usual personable self but a steeliness underpinned the 38-year-old's comments on Redknapp, Stewart Downing, England, players' wages and beginning with Ferguson.
"Unfortunately, we have had some matches against Manchester United with contentious decisions like the tackle [Emanuel Pogatetz on Rodrigo Possebon] and the penalty for the challenge on Cristiano Ronaldo,'' said Southgate, who angered Ferguson by defending Pogatetz and accusing Ronaldo of diving. "I have to fight my corner. But he [Ferguson] now totally understands that we completely respect them.''
United's manager even extended an olive branch 12 days ago with some conciliatory comments about Southgate. "I have had differences with him but his programme notes [before their Old Trafford meeting] were quite complimentary. Goodness me, I think him and Arsene Wenger are fantastic. I hold them, David Moyes and Martin O'Neill in the highest regard but that doesn't mean I don't want to take them on.''
He certainly took on Redknapp, telling the Spurs manager that Stewart Downing would not be heading south. "We are one place behind Tottenham, with the same points, and we don't think selling our best player to them would make sense,'' said Southgate, who sees Spurs as rivals in the race to avoid relegation. "Whatever their achievements in the past, that's where they are. We have to be firm.''
Southgate has certainly been firm with Downing. "I don't think it would be good for his reputation to leave. In a difficult time, and with Stewart a local lad, it wouldn't look right. Stewart should leave here under the right circumstances. He's a talent. Maybe at some point he will need to go somewhere else to get a sense of 'I can live in this company' and that brings more out of him.''
If that hinted Southgate could countenance the England winger departing in the summer, the manager's stance confirmed his mettle. "I don't think you play at the top level without being tough,'' reflected the former England international whose Boro side will need a collective toughness in Saturday's derby collision with Sunderland.
"The biggest lessons I would give my kids are good manners. People maybe take that as soft but those are the values I was brought up with. I want to win as much as anyone. I won't be put off-track by other managers. This is a tough job. We have seen that with what happened to a couple of young managers this year already [Roy Keane and Paul Ince].
"I accept at some point change might happen; we've seen everybody else go so why should we be any different? But me and Malcolm Crosby, my assistant, are the fifth longest-serving management team in the league and will give every ounce we have to do the job.
"Middlesbrough supporters want the team to play well and be committed. They want endeavour and effort. It is a hard-working Northern town and they expect people to put a shift in.'' Southgate will certainly be putting an exhausting shift in. "The job does stretch me mentally and emotionally but if I didn't want that challenge then 'get out'.
"I can understand why he [Keane] got out. I ask myself an awful lot: 'Why do I bother?' But something about the job grips me. It's what I know, what I am best qualified for. I have to accept that with the way the modern world is there will be huge amount of criticism with every decision I take. It is not just newspapers, it's television channels, internet, website, message boards. Everybody has a voice. Nobody did before.''
Everybody had an opinion, primarily abusive, when Southgate missed that penalty to send England out of Euro 96. "It's an unbelievable thing when you think how the tournament was going, the momentum behind England. The penalty gets played on the television, and Mia [his 10-year-old daughter] will ask about that.
"That toughened me. But I have been very fortunate in my life. The difficult experiences I have had have all been in football, and most of the other people I work with have had difficult experiences outside football.'' Like his coach, Colin Cooper, who lost a child in desperately tragic circumstances. "Exactly,'' nodded Southgate.
He keeps his family away from football, making sure they are shielded from the brickbats that fly the way of high-profile managers. "My kids go to a private school, a bit of a sheltered environment, in Harrogate, which is not really a football town. None of my family particularly likes football anyway. They very rarely come to matches. I have my  caps in an office but our house isn't a shrine to my career.''
Such a sense of perspective is fairly rare in football. "We do live in a bubble. There is a danger I can turn straight to the sports pages, go straight to Sky Sports News, and think we are more important than we are. For young players, Sky Sports News is on and they must think the whole world revolves around football. But what is going on in Israel is the reality of life.
"It is difficult for players. When I started at Crystal Palace, the highest paid player was on about £500 a week. They had come from Leicester reserves (Mark Bright), Greenwich Borough (Ian Wright) and Crewe (Geoff Thomas) and knew what it was like to be £50 a week. Now it doesn't come gradually, it comes overnight at 19, 20. That's incredibly hard for a young man to deal with.''
Southgate, the model of common sense, worked his way up as a player, and now as a manager, and is being mentioned as a potential England manager. "It is not something I am working towards,'' he stressed. "I have talked to Stuart Pearce about this and our view is that the job should be for someone with way more experience.
"It should be someone of Fabio Capello's age , real senior figures like Roy Hodgson, who has managed at international level (Finland) and been manager of Inter Milan, or Steve Coppell. They have proven themselves to be good managers. I can see one of that generation coming through (after Capello).'' And perhaps Southgate after that. He possesses the toughness.