The Three Lions fielded an inexperienced eleven with three players making their maiden worldwide appearances, Tammy Abraham joining Loftus-Cheek and Pickford, and totalling just 101 caps with only five players on 10 or more.
"To go to the World Cup it's a long season and I still have to improve".
The Three Lions' starting lineup was made up of just one player aged 30 or over - Jamie Vardy - while five stars were handed their senior bows by Southgate on the Wembley turf.
On his side's overall performance, Southgate added: 'We created a couple of really good chances and I felt our use of the ball was excellent throughout the game. I don't think the wider public will be as aware of him, you would have to have followed him very closely, but we believe in him and the others we played.
"He's certainly made really important saves tonight".
"It was a brilliant experience for our players and we've now got to see if we can try and replicate that against a side who rested a lot of their players today on Tuesday".
Stoke City's Butland was one of seven players to pull out of Southgate's initial 25-man selection ahead of the clash with Die Mannschaft, and the ex-Middlesbrough boss has confirmed he will call in replacement from the under-21s. I'll find out whose played well tonight, who warrants the decision.
Loftus-Cheek was pulling the strings in midfield as England pushed for a goal, including feeding captain Dier to get away a cross that Mats Hummels had to hack behind his own goal.