Brighton midfielder Gross blasted a rocket past German-born Greece goalkeeper Odysseas Vlachodimos in the final minute to win the match for the home side, after Kai Havertz earlier cancelled out Georgios Masouras' opener.

Despite coach Julian Nagelsmann naming his strongest XI, Germany lacked fluidity against the 2004 Euros winners, who did not qualify for this summer's tournament, having lost a play-off qualifier to Georgia on penalties.

Germany goalkeeper Manuel Neuer was at fault for Masouras' 33rd-minute opening strike, clumsily spilling the ball in front of goal having previously gone unpunished for a late error in Monday's scoreless draw with Ukraine.

The mistake calls into question Nagelsmann's pre-tournament promise that the 2014 World Cup winner would line up between the sticks, with Barcelona goalie Marc-Andre ter Stegen waiting in the wings.

Real Madrid's Toni Kroos and Antonio Ruediger returned for Germany, having missed Monday's match due to their Champions League celebrations. The duo's return allowed Nagelsmann to name his strongest team -- and the side likely to take the pitch in next Friday's tournament opener against Scotland.

The visitors started strongly, Christos Tzolis forcing a desperate double-save from Neuer just six minutes in, the 38-year-old 'keeper denying the Fortuna Duesseldorf striker with his foot and then his hand from close range.

Ranked 50th in the world, Greece continued to cut through a lacklustre German midfield and hit the lead after 33 minutes when Neuer spilled a Tzolis shot into the path of Masouras, who tapped home from a metre out.

The goal silenced the home crowd, who had been in full voice and had unveiled a banner saying "we will become European champions" before the match.

Havertz had the ball in the net just before half-time, but was narrowly offside before collecting Jamal Musiala's pass.

But the Arsenal striker then did get on the scoresheet 11 minutes into the second-half, collecting a Leroy Sane pass and slotting home on the turn.

Second-half substitute Benjamin Henrichs rattled the crossbar with seven minutes remaining from distance but Gross, who also came on midway through the second-half, would go one better, slamming a long-range effort into the top corner.

Germany will welcome the victory but questions remain, particularly in goal.

Neuer, who missed close to a year of football having broken his leg after returning from Qatar in December 2022, also made a crucial error against Real Madrid as Bayern were eliminated in the Champions League semi-finals in May.