Sancho missed training on Thursday following news of his gran’s passing, and was even asked by Dortmund sporting director Michael Zorc before Saturday’s game whether he was emotionally fit to play.
But he started and netted the decisive goal with a sensational solo effort, becoming the first Englishman and the youngest ever player to score in the Revierderby, aged 18 years, eight months and 13 days.
The previous record-holder was Dortmund legend Lars Ricken, who scored in the Revierderby as a 19-year-old, in October 1995.
"The goal means everything to my family," Sancho told bundesliga.com. "Sadly my grandmother passed away, so that goal was for her. I’m glad that I got the goal and helped the team to get three points."
Watch: Jadon Sancho reflects on his emotional match-winner
'Sancho wanted to play' - Favre
Sancho was understandably overcome with emotion following his goal. Kissing his hands and pointing to the skies, he dropped to the turf in tears before being consoled by his team-mates.
"It was a very difficult week for him," said BVB head coach Lucien Favre. "He’s 18, and lost his grandmother. He only flew back from London on Friday, but he really wanted to train and play."
Great feeling to get the Winning goal in the big Derby. Massive effort from all the boys and staff. Been a tough week personally, dedicating my goal to my Nana! I love you forever n ever 😢❤️! I know you’ll be smiling down on me! See you soon my Angel 😔❤️🙏🏼😢 pic.twitter.com/2aFe2eBh8O— Jadon Sancho (@Sanchooo10) December 8, 2018
Reus lauds 'sensational' Sancho goal
Sancho’s strike was his sixth in the Bundesliga since leaving English Premier League side Manchester City in summer 2017, and fifth in 13 appearances this season. He also has six Bundesliga assists so far this term.
"I'm really happy his effort paid off," said Dortmund captain Marco Reus. "I've got so much respect for the mentality he showed. And hats off to him for being able to train, focus and laugh again. He scored a sensational goal - it was the kind of thing we practise in training. We fully deserved to win."
Dortmund still unbeaten
Bundesliga leaders Dortmund are now unbeaten in 14 Bundesliga matches since the start of the season, and sit some nine points clear of defending champions Bayern Munich.