The 25-year-old’s inclusion even allowed the Three Lions to have a dash of Marcelo Bielsa.
Leeds-born Phillips was the outstanding player and not only because of the part he played in teeing Raheem Sterling up for the only goal of the game against Croatia.
It meant England have won their opening match at the European Championship for the first time in their history.
As he often has for England, Phillips played as a “No 8”, in advance of Declan Rice, who played the holding role which is where the Whites player usually is for Leeds.
But Southgate pointed to Phillips’s skill and athleticism as to why he has no fears about asking him to do the job, and the midfielder’s debut performance in tournament football fully justified it.
“We watched him a lot the season before last in the Championship and were going to bring him into the squad ahead of the Euros a year ago,” said Southgate. “He’s now had a season of Premier League football, and he’s technically good, and we also knew the athleticism in midfield was going to be important.
“We had to get tight to their midfield players and Mason (Mount), Kalvin and Declan did that really well. They did a lot of the job for the defence to limit the opportunities.
“Kalvin is a fabulous boy to work with, so unassuming, and I thought his performance was outstanding. There were two first-half passes (to Kyle Walker and Phil Foden) behind their defence that were top level and the contribution for the goal summed his day up, really.
“We know we’re asking him to play in a slightly advanced position from where he plays for his club, but he’s got the technique to be able to do that. It gives us a bit more solidity in midfield and allows us to effectively play four attacking players with Mason in midfield as well.
“We think that three in midfield is a good balance, but I have to credit the forwards for doing their job without the ball as well, every time we made runs in behind we looked a real threat, we could have done that a bit more if anything. I’m pleased with a lot of things, although as always, there are things we can still get better at.”
Of his assist for Sterling, Phillips said: “It was just instinct. I knew I was in a good position. I wouldn’t say I work on it every single day but I felt I had it in my locker.”
Phil Foden hit the base of the post in the opening five minutes as England made a fantastic start to the game without scoring. Ironically, it was when Croatia enjoyed their best period of the game that England were able to score.
Phillips’s game has improved beyond recognition under former Argentina and Chile coach Bielsa. Twelve months ago he had not played top-flight football, never mind international level.
“To be able to work with the coach he has and have a season of playing in the Premier League will have given him tremendous confidence,” reflected Southgate. “But all those attributes were there – the range of passing, the athleticism, the desire. For us, he’s just a very good footballer. High performance, low maintenance – we like that a lot.”
The format of the competition, with four of the six third-placed teams reaching the knockout stages means a win has already put England in a strong position to progress. They still have Scotland and Czech Republic to play.
“It feels great to have been able to send the fans home happy, and to have fans up and down the country happy, that’s very special,” said Southgate. “I was pleased with the way we settled so quickly. There were some young, inexperienced players, and it was a big occasion against a big team on a sweltering hot day, so there was every reason to look nervous at the start, but they didn’t. With and without the ball, they carried out what we wanted to do in terms of pressing brilliantly.”