"What we saw in the second half was very positive", the German said.
But Alli opted to represent the place of his birth, and where he was raised, first pulling on an England shirt in 2012 with an appearance for their under-17 side.
Goals from Gary Cahill and captain Harry Kane put the Three Lions into a deserved half-time lead, but Nigeria hit back after the break and pulled one back through Arsenal's Alex Iwobi. But we also know his quality on the ball when he's in the final third.
But a change in formation caused confusion among the England players as Nigeria opted to match their opponents man for man.
The 23-year-old spurned a number of chances to score at Wembley before being cautioned for diving in the second half.
Pickford is only 24 and relatively inexperienced, but he will have gained confidence from an error-free performance in the win. If we can win our first game, I am sure we can get to the quarterfinals. "We've got to prepare right to go as far as we can".
He added: "We would have conceded more goals in the first half but this young team does not give up".
"I think first and foremost he has conducted himself fantastically well this week, he has managed that situation very well".
"So credit to him he has had to come over that but it is to be expected for whatever reason".
After facing Nigeria, England go up against Costa Rica at Elland Road on Thursday - their final official warm up match before travelling to Russian Federation.
Germany led early on through Mesut Ozil's strike but second-half goals from Martin Hinteregger and Alessandro Schopf turned the match on its head and gave Austria, who will not be at the World Cup in Russian Federation, a seventh successive victory.