ISTANBUL - Chelsea renew acquaintances with former hero Didier Drogba and an old rival in Roberto Mancini when they go to Istanbul to take on Galatasaray for the first leg of their Champions League last-16 tie on Wednesday. Drogba was the hero of Chelsea's 2012 final victory against Bayern Munich, scoring a late equaliser to force extra-time and then netting the decisive penalty in the shoot-out that followed. But the powerful Ivorian centre-forward was also one of the cornerstones of Jose Mourinho's first spell in charge at Stamford Bridge, with the pair arriving at the same time in 2004."It's a strange feeling," Mourinho said, having previously expressed a wish that the clubs would come out of the hat together before the draw was made. "We know him well and that means there will be no friends during the game. We have respect for a real legend of this club before the game and after the game, but we have a job to do. It's in his nature to win and to score, but we have to stop him."For Mourinho, coming up against Drogba is nothing new - his Real Madrid side beat Galatasaray 5-3 on aggregate in last season's quarter-finals despite Drogba scoring for the Turks. The tie will also see the Chelsea manager come up against Dutch playmaker Wesley Sneijder, who was the driving force of his Inter side that won the Champions League in 2010 and moved to Istanbul last year.There is also the enticing prospect of seeing Mourinho in direct confrontation with Mancini, the man he replaced as coach of Inter in 2008, and the man who locked horns with the London club during his tenure at Manchester City. Beyond the sub-plots, though, Sneijder believes Galatasaray's inside knowledge on Mourinho's methods gives them a good chance of springing a surprise. "Mourinho knows us well and that is an advantage but the same applies for us, we know Mourinho very well, perhaps better than the Chelsea players know us," said the 29-year-old, who also told Turkish media that his former mentor had called him immediately after December's last-16 draw.Chelsea did not exactly convince en route to winning their Champions League group ahead of Schalke 04 and Basel, losing both meetings with the Swiss side. However, without the distraction of European football over the winter, they have emerged as serious contenders to win the Premier League title, a 12-match unbeaten run putting them top of the table, a point ahead of Arsenal.Over two legs, they are the clear favourites to get the better of Galatasaray, even if the Turkish side progressed from their group at the expense of Juventus and can count on a hostile home support at the 52,000-capacity cauldron of the Turk Telekom Arena. Mancini's side beat city rivals Besiktas 1-0 at the weekend with a Selcuk Inan penalty to keep the pressure on Fenerbahce in their domestic Super Lig, and have lost just once in 19 games.However, the Italian insisted in an interview with British radio station TalkSport last weekend that something special would be required for his side to beat Chelsea, with a 6-1 home loss to Real Madrid at the start of the group stage indicating the size of the gap that separates Galatasaray from Europe's elite. "We went through in a difficult group with Real Madrid and Juventus and I think it was a miracle," he said. "Now we are here and I don't know if we can do another miracle but we want to try. In football never say never."Chelsea, whose January signings Nemanja Matic and Mohamed Salah are ineligible to feature in Europe, travelled to Turkey on Monday evening with David Luiz and John Mikel Obi both included in the party despite missing the weekend's 1-0 win against Everton. Oscar, substituted in that game with an ankle problem, also flew out with the squad, who would love a repeat of the scoreline the last time the clubs met in Istanbul in 1999. On that occasion, they ran out 5-0 winners, with Norwegian striker Tore Andre Flo scoring twice.