Stoke City goalkeeper Jack Butland started in goal, and was unable to keep out Toni Kroos’s low drive before coming off injured just before half time.
Forster was the man to replace the Potters stopper, coming on for his first England appearance since rupturing his patellar tendon just over a year ago.
The Saints goalkeeper made an impressive stop just after half time, as he tipped away a free-kick from Marco Reus that had evaded everyone in the penalty area.
But he could do nothing ten minutes later to prevent Germany from doubling their lead. Sami Khedira’s cross found Mario Gomez, and his header left Forster with no chance as it snuck inside the far corner.
England grabbed themselves a lifeline moments after, as an excellent turn from Harry Kane afforded him time in the penalty area, and he made no mistake as he found the bottom corner with a low strike.
Roy Hodgson made a double substitution with 20 minutes remaining, and it was one of those introductions who levelled. Former Saint Nathaniel Clyne crossed, and Jamie Vardy was on hand to flick the ball superbly beyond Manuel Neuer.
And the comeback was complete when Eric Dier headed Jordan Henderson's corner beyond Neuer in stoppage time.