Germany squandered a three-goal lead to draw 3-3 against Italy on Sunday but still earned a nerve-racking 5-4 aggregate victory to set up a Nations League semi-final against Portugal in June.

The hosts scored three times, including one goal aided by a quick-thinking ballboy, in a dizzying first half where they dominated their continental rivals with a high-pressing and attacking game that left Italy no chance.

Not since their 2014 World Cup victory had Germany outclassed a major international side in such a way for an entire half, with 16 efforts towards goal. But they were nowhere to be seen after the break, taking their foot off the gas and conceding three goals before snatching a slim aggregate win.

"It was the best half, very impressive first half, incredibly aggressive and a deserved lead," said Germany coach Julian Nagelsmann.

"In the second half our lineup was a bit different. Then there are moments you concede a goal, then another and then the team that had not played together like that started feeling the pressure," he added.

"But what we learned from these two matches is important for our development."

Influential Kimmich

The Germans, who won the first leg 2-1, shot out of the blocks and opened their account with Joshua Kimmich's 30th minute penalty.

Before the Italians had time to recover, Germany struck again, catching keeper Gianluigi Donnarumma and the entire defence napping with a quickly taken Kimmich corner for unmarked Jamal Musiala to slot in their second in the 36th minute.

The Italians were still discussing among themselves when 15-year-old debutant ball boy Noel Urbaniack speedily threw the ball back for Kimmich to take the corner. The teenager was given a ball signed by the German team after the game.

Tim Kleindienst added a third on the stroke of halftime with a close-range header from yet another Kimmich assist and another defensive error by the visitors as the hosts looked to be cruising to a comfortable win.

It was Kimmich's fourth assist over the two legs but it would not be enough for victory with the Italians pouncing on a German mistake to hit back four minutes after the restart through Moise Kean.

With the Germans a shadow of their earlier selves, Kean then beat defender Jonathan Tah in the 69th minute to make it 3-2.

Italy drew on the night with Giacomo Raspadori's stoppage-time penalty but could not find another goal to level the tie on aggregate.