Match ends, Borussia Dortmund 3, Tottenham Hotspur 0.
Much-changed Tottenham were outclassed by Borussia Dortmund, who took a commanding lead into the second leg of their Europa League last-16 tie.
With seven alterations, Spurs struggled to contain the hosts and were fortunate Pierre-Emerick Aubameyang's header was the only difference at half-time.
Gonzalo Castro hit the post before Marco Reus rifled in at the back post.
Son Hueng-min had a penalty appeal turned down but Reus then scored a half-volley after a flowing move.
Tottenham's heaviest defeat of the season leaves them a mountain to climb against a Dortmund team who must be considered one of the favourites to win the Europa League this season.
And in Mauricio Pochettino's 100th game in charge, his team selection perhaps showed that lying second in the Premier League is a more valuable commodity as Spurs seek to win a first top-flight league title since 1961.
Inexperience costs Spurs
Both teams are second in their domestic leagues and five points behind respective leaders Bayern Munich and Leicester, yet there was a gulf in class at the Westfalenstadion.
And with bottom-of-the-table Aston Villa Tottenham's next opponents on Sunday, questions will be asked about Pochettino's decision to rest Eric Dier and leave Harry Kane, Mousa Dembele and Erik Lamela on the bench, particularly from 3,400 travelling fans.
The young side could have done with more assistance, especially in midfield. Ryan Mason and Tom Carroll replaced Dembele and Dier, and could not cope as their opponents swarmed forward in the first half.
Only the experience of defenders Toby Alderweireld and Kevin Wimmer kept the scoreline at 1-0 at the break with Erik Durm sliding wide and Aubameyang having a goal disallowed after Hugo Lloris saved Henrikh Mkhitaryan's stinging shot.
Spurs also showed naivety for the two opening goals, failing to clear the ball before Aubameyang rose to head in from Marcel Schmelzer's cross, and slow to press from the corner where Reus smashed in Neven Subotic's header.
Thomas Tuchel's team cut through the heart of the midfield to set up Reus for the third, the kind of goal which the rested Dier perhaps would have prevented.
Dembele, Lamela and Kane were all introduced but they made little difference against a team who have not lost at home in 2016.
Dortmund still worthy of Champions League
Dortmund have competed in the Champions League for the past four seasons and are only in the Europa League after a poor start to last year's domestic campaign under previous boss Jurgen Klopp.
But under Tuchel they have regained their former lustre, chalking up 12 games unbeaten in all competitions. At times, they mesmerised Spurs with quick interchanges in midfield and clever wing play.
Aubameyang scored his 33rd of the season, and could have grabbed two others, as he was ably supported by Mkhitaryan and Castro in attacking positions, with Reus and Durm offering dynamism from the flanks.
Dortmund have never won the Europa League, or the Uefa Cup as it was previously known, but on this evidence it will take a very strong performance to stop them reaching the final in Basel, and perhaps even lifting the trophy.
Man of the Match
Tottenham boss Mauricio Pochettino: "It is difficult to explain but it's a bad day and I'm disappointed with our performance. We did not play well. That is why we lost the game.
"We need to fight in the return leg next week. Three-nil is not a good result for us but we still need to keep working hard and try next Thursday.
"This was our first time losing 3-0 this season. We need to be calm and be sure it doesn't happen again."
Tottenham take their Premier League challenge to bottom-of-the-table Aston Villa on Sunday while Dortmund host Thomas Tuchel's former team, Mainz.
- 6BenderSubstituted forSuboticat 58'minutes
- 11ReusSubstituted forRamosat 82'minutes
- 17AubameyangSubstituted forKagawaat 82'minutes
- 28CarrollBooked at 35mins
- 23EriksenSubstituted forLamelaat 65'minutesBooked at 67mins
- 7Son Heung-MinSubstituted forKaneat 76'minutes
- 22ChadliSubstituted forDembéléat 58'minutes
- Cüneyt Çakir
- Shots on Target
Second Half ends, Borussia Dortmund 3, Tottenham Hotspur 0.
Roman Weidenfeller (Borussia Dortmund) wins a free kick in the defensive half.
Foul by Erik Lamela (Tottenham Hotspur).
Attempt missed. Henrikh Mkhitaryan (Borussia Dortmund) left footed shot from the left side of the box misses to the right. Assisted by Erik Durm.
Foul by Erik Durm (Borussia Dortmund).
Tom Carroll (Tottenham Hotspur) wins a free kick in the defensive half.
Foul by Mats Hummels (Borussia Dortmund).
Harry Kane (Tottenham Hotspur) wins a free kick in the defensive half.
Substitution, Borussia Dortmund. Adrián Ramos replaces Marco Reus.
Substitution, Borussia Dortmund. Shinji Kagawa replaces Pierre-Emerick Aubameyang.
Foul by Marco Reus (Borussia Dortmund).
Tom Carroll (Tottenham Hotspur) wins a free kick on the right wing.
Substitution, Tottenham Hotspur. Harry Kane replaces Son Heung-Min.
Attempt missed. Henrikh Mkhitaryan (Borussia Dortmund) right footed shot from the centre of the box is too high. Assisted by Marcel Schmelzer.
Marcel Schmelzer (Borussia Dortmund) wins a free kick in the defensive half.
Foul by Erik Lamela (Tottenham Hotspur).
Foul by Henrikh Mkhitaryan (Borussia Dortmund).
Mousa Dembélé (Tottenham Hotspur) wins a free kick in the defensive half.
Attempt saved. Son Heung-Min (Tottenham Hotspur) left footed shot from the right side of the box is saved in the centre of the goal. Assisted by Kieran Trippier.