The Dutch came from behind to beat Turkey 2-1 in Berlin on Saturday in a tense quarter-final, with the balance tipped in their favour by the burly Burnley striker's appearance from the bench.
With Turkey comfortably sitting 1-0 up at half-time fervently backed by raucous support at the Olympiastadion, Ronald Koeman rolled the dice and called for his wildcard option.
Weghorst burst into football's global consciousness with a stunning brace as a substitute against Argentina in the 2022 World Cup quarter-final and is still devastating in that role.
The 31-year-old six-foot-six striker rescued the Netherlands a 2-1 win over Poland in their Euros opener with a well-taken goal off the bench.
Koeman restricted Weghorst to 44 minutes across the Netherlands' opening four matches but gave him a full 45 against Turkey and it paid dividends, as the team booked a semi-final date with England.
Instantly the Dutch had a target to aim for in the box, with Memphis Depay's drifting denying them a focal point until Weghorst's appearance.
"Because of (Weghorst) you create a little bit more chaos in the box and they have to defend more, so I think Wout helped a lot," said Dutch defender Nathan Ake.
"He's a nightmare to play against. He is strong, is a nuisance in a box and he fights for everything. He runs off everything. So for us he is a great asset."
Weghorst, who spent the season on loan at Hoffenheim, put the jitters into Turkey's previously solid defence.
Mert Gunok's save from Weghorst led to the corner from which the Netherlands equalised, with Stefan de Vrij heading home Depay's cross.
With the Turkish rear-guard tying themselves in knots to stifle Weghorst, the Netherlands netted again six minutes later with Mert Muldur, under pressure from Cody Gakpo, bundling into his own net from Denzel Dumfries' raking ball.
"We started quite well but it changed after 20 minutes, (then) they were dominating," explained Koeman.
"Then it was clear for me to make this substitution with Wout, with Cody on the wing and Denzel on the right, we had to have a lot more crosses than in the first half."
'Wout could be Wout'
Liverpool winger Gakpo leads the Netherlands squad for goals and is also the competition's joint-top scorer with three strikes in Germany, but he paid tribute to Weghorst's huge impact off the bench.
"It's different (with him on)... in this game when we wanted to play a little bit more opportunistically, then you can bring Wout because he's tall, he's good in the air, he fights for every ball that comes in the box," Gakpo told reporters.
"So, that's what we tried in the second half in the beginning. We played some good crosses and then we saw the Turkish side dropping a little bit more, so we could play better.
"Maybe that was the key today. I'm very happy that Wout could be Wout today. Top."
Next up for the Dutch is England, a country where Weghorst has struggled to make much of an impact.
He signed for Burnley in 2022 from Wolfsburg but only netted twice in 20 games with his side relegated from the Premier League.
A half-season loan to Manchester United ended with no top flight goals in 17 appearances, so making an impact against the Three Lions would provide him with some extra satisfaction.
Koeman said earlier in the tournament Weghorst has "English qualities" and was certainly an option to start, even though it has not happened yet.
Given his ability to make a difference as a plan B, Koeman may wish to keep him in reserve as the 1988 winners face their first Euros semi-final since 2004 on Wednesday in Dortmund.
