Chris Coleman's charges, however, will only need a point to be certain to progress to the next stage if England avoid defeat to Slovakia on Monday.
"We just need to continue what we have been doing both on the pitch and off the pitch. Nothing changes. There are a lot of positives we can take and maybe the thing we can improve on is keeping the ball a bit better," Ledley was quoted as saying by British media.
"We are in a fantastic position and we need to regroup, we can still progress and it is in our hands. There is a big game in a few days and we must stay strong and stay together."
Ledley, who recovered from a leg fracture in order to play at Euro 2016, lasted 67 minutes against England before being substituted with a calf problem.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The 29-year-old, however, declared himself fit for the decisive group clash against Russia.
"It is OK, I felt my calf tightening up a bit during halftime and once I got a bang on it, it stiffened up a bit and we needed to take the precaution with it," he said. "I could have played on but the lads said not to risk it."
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by Toby Davis)
