Besiktas end United's home run
Already-qualified United, who have reached the last two finals in the competition, had not lost at home in their previous 23 Champions League matches, since a 1-0 defeat to AC Milan in February 2005. But a deflected effort from Chilean winger Tello was enough for Besiktas, who had only picked up one point from their previous four matches. United now need a point from their final match, away to German champions Wolfsburg, to qualify as Group B winners.
With qualification already wrapped up, Sir Alex Ferguson made eight changes to the team that beat Everton 3-0 at the weekend. That included a recall for Korean star Ji-Sung Park, who had not featured since the 4-3 win over Manchester City at the end of September due to a knee injury.
And despite a positive opening from the hosts, it was Ben Foster - making his first United appearance since 3 October - who was the first goalkeeper tested, following a powerful drive from Michael Fink. Besiktas only had the slightest chance of finishing third and reaching the Europa League but maintained their pressure, with Ismail Koybasi firing wide.
United responded with a Nemanja Vidic header that flew well off-target and a long-range effort from Darron Gibson that just missed Rustu Recber's goal. Federico Macheda also went close with a powerful run and a low shot that trickled narrowly wide. But in the 20th minute the Turkish side took the lead with Tello's shot flying off United defender Rafael and past Foster.
Macheda was at the heart of United's best work and slipped Danny Welbeck in behind the Besiktas defence and his low effort was turned wide by Recber. The veteran goalkeeper was worked again when Welbeck guided a pass through for Gabriel Obertan and the impressive French winger's stab at goal was turned away.
Republic of Ireland midfielder Gibson blasted well over the bar to continue United's frustration as the interval approached, while the visitors could have doubled their lead just before the break when Bobo laid the ball back and Fink's delicate shot bounced wide off the outside of the post.
No United spark
There was little response from United after the re-start but there was little positive play from the visitors either, with Tello failing to trouble Foster with a free kick from 25 yards. But after Gibson sparked a quick break, the ball was worked left and Park shot wide under pressure from two defenders.
Just past the hour mark, a mazy run from Obertan took him past two Besiktas players before his low shot was pushed wide by Recber and the Frenchman went close again moments later with a looping header from Macheda's cross that dropped onto the roof of the net.
Mid-way through the second half, Ferguson brought on Michael Owen for Park as he stepped up his search for an equaliser. But there were few chances for the hosts to get back on terms, with another substitute, Michael Carrick, hitting a free-kick straight against the wall.
With five minutes remaining, substitute Patrice Evra had a penalty appeal turned down after going down in the box under a challenge from Ibrahim Kas. Recber also pushed over a Macheda header from Anderson's cross and then made a superb save from the resulting corner to deny Wes Brown, before keeping out another Carrick strike in injury time to earn Besiktas a memorable victory.