Claudio Pizarro came back to haunt Jose Mourinho by scoring the opening goal as Werder Bremen earned a place in the UEFA Cup and denied Inter Milan top spot in Champions League Group B.
Pizarro reminded Mourinho of exactly why the Portuguese signed him for Chelsea when he pounced on a loose ball to slide home just after the hour.
Markus Rosenberg scored the hosts' second after 81 minutes and, despite Zlatan Ibrahimovic's late consolation, Bremen finished third in the pool thanks to Panathanaikos' win over Anorthosis Famagusta.
Having already ensured their passage to the next round, Inter coach Mourinho rested five players from the side that hammered Lazio 3-0 at the weekend to record their sixth straight Serie A victory.
Brazilian striker Adriano made a rare start in place of top goalscorer Ibrahimovic while Nicolas Burdisso, Mancini, Marco Materazzi and Ricardo Quaresma also started.
Bremen's season has been a complete contrast to the Nerazzurri's. Last month's draw at Anorthosis meant the German side could not qualify for the knockout stages
To make matters worse, their influential playmaker Diego was suspended for the clash.
Bremen did not look like they were missing Diego early on as they took the game to the Italian champions from the start.
Thomas Schaaf's side won two corners and forced Julio Cesar into a save in the first minute when he had to hold on to a Mesut Ozil header.
Inter began to find their feet and took the game to the hosts with Mancini and Quaresma pulling the strings behind lone striker Adriano.
Mancini played through Adriano 18 minutes in but the forward could not stop the ball running away from him after he tried to steer his way past an on-rushing Tim Wiese.
Bremen enjoyed their most fruitful period towards the end of the first half with Pizarro posing the biggest threat.
The on-loan Chelsea striker latched onto Ozil's corner but the Peruvian headed straight at Wiese from close range.
He then thought he should have had a penalty when he had his shirt pulled by Oscar Cordoba in the box but referee Pieter Vink waved his protests away.
Mourinho then threw on Ibrahimovic and Brazilian defender Maxwell in a bid to get a grip of the game.
It was Burdisso, however, who almost broke the deadlock nine minutes after the break but his header was cleared off the line by Clemens Fritz.
Pizarro then made Inter pay when he was the quickest to react to Cesar spilling Ozil's shot to tap home and put the Germans one foot into the UEFA Cup just after the hour.
Pizarro threatened once more soon after when he wrong-footed Burdisso but his shot was stopped by Cesar who had to make a low save to his right.
Ozil continued to be a constant threat for Bremen and the German squared to Rosenberg who hit the second after 81 minutes.
Ibrahimovic's superb late strike from outside the box pulled one back for Inter but it proved to be nothing more than a consolation for Mourinho's side who slipped to their second Champions League defeat of the campaign.
