Victor Osimhen has scored six goals in his last five games
Victor Osimhen scored twice as Galatasaray inflicted a first Europa League defeat of the season on 10-man Tottenham in Istanbul.
Teenage forward Will Lankshear was dismissed for two yellow cards on the hour mark for Spurs, having earlier scored his first senior goal for the club in only his second start.
However, by that stage the visitors should have been out of sight with the final scoreline barely reflective of an encounter that was dominated by the hosts.
Despite the result Ange Postecoglou's side still remain well placed to qualify from the group stage, with nine points from four games, although the Turkish league leaders have now leapfrogged above them in the table.
Tottenham's woeful attempts to play out from the back and their shambolic defending ensured they endured a trying evening in a destination that is notorious for its hostile atmosphere.
Yunus Akgun's sixth-minute effort was the precursor of what was to follow, with the Turkey midfielder dispatching a wonderful left-foot volley past Spurs goalkeeper Fraser Forster from 20 yards.
While 19-year-old Lankshear levelled from close range after being teed up by Brennan Johnson, the way in which Tottenham repeatedly gifted possession and goalscoring opportunities to their opponents will place scrutiny on manager Ange Postecoglou's decision to begin with six first-choice players on the bench.
An error from central defender Radu Dragusin contributed to Osimhen's first goal of the evening, with the on-loan Napoli forward reacting sharply to a Dries Mertens pass to poke a right-foot effort past Forster into the right corner.
Osimhen's second also came courtesy of the Belgian playmaker, with Mertens' right-wing delivery expertly turned home by the unmarked Nigerian international from eight yards.
While substitute Dominic Solanke tapped in from Pedro Porro's pass - nine minutes after Lankshear's departure - to give the score an air of respectability, in truth the visitors were well beaten.
Only some profligate finishing and several excellent saves from Forster prevented Okan Buruk's team from the emphatic victory they richly deserved.
Lankshear's mixed fortunes on night to remember
Forward Lankshear, who arrived at Spurs from Sheffield United in 2022, penned a new five-year deal with the north London club in the summer.
And after enjoying a prolific campaign for Tottenham's under-21s team last term, he will have been delighted to get off the mark for the first team having been granted a rare opportunity to impress.
His goal came with his only touch in the Galatasaray penalty area and, while he had little to do, he still deserves credit for being in the right place at the right time to convert the simplest of chances.
However, having collected a relatively frivolous yellow card while trying to back into a defender, he then soured his night's work with a reckless challenge on former Norwich attacker Gabriel Sara just seven minutes later, which was borne out of his frustration at losing the ball cheaply.
While that may earn a rebuke from his manager, the manner of Tottenham's overall display would leave few in their dressing room fortunate to escape a Postecoglou scolding.
Many of the hosts' 28 efforts on goal were of the visitors own making and while they improved after going a man down, they always looked vulnerable at the back.
