'No better feeling', says Sancho after firing Dortmund into last eight
The Manchester United loanee opened the scoring in the third minute, his first goal in front of Dortmund's 82,000-strong home crowd since May 2021.
Marco Reus added a goal in stoppage time to seal the win, putting Dortmund through 3-1 on aggregate, making the last eight for the first time since 2021.
"It was like a relief. I think like all players you want to have a good start to the game -- and there's no better feeling than that," Sancho told TNT Sports.
"I'm just grateful that I could get a goal for the team.
"We knew it was going to be tough, but I felt we'd have the advantage because we're playing in front of our home fans."
Sancho, 23, had an unhappy time at Manchester United and had been forced to train away from the first team having fallen out of favour with coach Erik ten Hag.
Having only made three appearances in the Premier League this season, the winger arrived in Dortmund for his second spell at the club in January on a six-month loan.
He came into Wednesday's game saying he could "understand fans getting frustrated" with his output, but has now scored twice in two games.
"I've always got a special place for Borussia Dortmund," Sancho said on Wednesday.
"This is where I made my name. I have to be grateful to them and to my teammates for believing in me.
"I'm just happy we got the win today."
Dortmund coach Edin Terzic, who coached Sancho during the Englishman's first stint in Germany, praised the winger.
"I'm happy for Jadon that he scored. He had a really great game," Terzic told reporters.
"I think that today Jadon showed us his best performance since he returned to us."
Terzic said Dortmund and Sancho were being rewarded for their patience.
"It was only seven days ago when everyone was asking 'What's happening with Jadon, why hasn't he scored?'
"Now he has two goals."
Sancho was substituted with 15 minutes remaining while clutching his thigh, but said: "I felt something and I just didn't want to risk it.
"We're gonna check and hopefully it's nothing."
Terzic added: "He felt something in his leg, but we hope that he comes through it healthy and that he'll be available for us this weekend."