Spain had dominated possession, but they had struggled to break through a resilient defence in Zurich as Christian Wuck’s side dug deep to force extra time.
But with the game looking destined for a penalty shootout, Bonmati stepped up when it mattered – sending Spain to their first Women’s Euro final.
“It was not easy for [Bonmati] at the beginning of the tournament but she has a special personality to be at the maximum level,” said Spain boss Montse Tome.
Bonmati had cleverly darted into space between Germany defenders Rebecca Knaak and Franziska Kett, before receiving Del Castillo’s pass on the half-turn.
Despite the tight angle, she buried the ball in at the near post.
“Top-class players turn up in the moments and that’s what Spain needed. That’s why Bonmati is a Ballon d’Or winner,” ex-Scotland defender Jen Beattie said on BBC Radio 5 Live.
Former England defender Steph Houghton added: “I honestly thought from Spain’s point of view she was definitely their best player and she’s got them through to their first-ever European Championship final.”
The goal sent the Spanish fans at Stadion Letzigrund into pandemonium, while the scorer was immediately embraced by members of La Roja’s bench.
“When the ball was in, I started running and I saw the bench standing so I celebrated with them,” said Bonmati.
“Scoring in a game like this one is super-special. If I can help the team write history, it’s very special.”
She added: “I was confident in my mentality and my physical situation. I wanted to get to this game at my best level. Thanks to all people who were next to me to help me reach this level.”