Hamburg:Fenerbahce came from a goal down to stun Chelsea 2-1 in Champions League football while in the other quarterfinal first-leg tie, Liverpool and Arsenal played out a 1-1 draw.
In London, Liverpool came from a goal down to draw 1-1 with Arsenal at the Emirates, also Wednesday night.
Chelsea got off to the perfect start in Istanbul when Deivid turned Florent Malouda's cross into his own goal after just 13 minutes and Michael Essien nearly doubled the English side's lead five minutes later but his long-range shot came off the crossbar.
Fenerbahce created very little in the first half but with Drogba missing a couple of half-chances, the home side came out firing after the break and another Brazilian, Alex, headed wide from a good cross by Onder Turaci.
Frank Lampard mis-hit a shot wide and Drogba was again denied by Demirel while at the other end, former Chelsea striker Mateja Kezman saw an acrobatic bicycle kick saved by Carlo Cudicini.
The turning point came when Englishman Kazim Kazim, whose English name is Colin Kazim-Richards, came on for Fenerbahce and after Demirel tipped away a Michael Ballack effort, the former Sheffield United striker ran on to a long ball and smashed it past Cudicini.
Fenerbahce then took the lead when Deivid hit an incredible 30-metre strike past Cudicini in the 81st minute to send the Turkish fans crazy.
Chelsea tried to grab the equaliser but they were unable to find a way past the excellent Demirel as Fenerbahce held on for the win, though Chelsea will fancy their chances of going through by winning the second leg at Stamford Bridge.
In London, Arsenal started strongly and deservedly took the lead after 23 minutes when Emmanuel Adebayor rose unchallenged to head home a Robin van Persie pass from six metres against Liverpool.
The lead lasted just three minutes, however, as Dirk Kuyt bundled the ball home from a similar distance after some excellent build-up work on the left from Steven Gerrard.
The Dutch forward has had his struggles domestically this season, but it was his sixth goal in European competition.
"The goal was really important," said Kuyt afterwards. "We wanted to score and we did."
He very nearly added a seventh shortly after half time, but Manuel Almunia was able to grab his shot at the second attempt as Sami Hyypia closed in.
Arsenal took control again after that. Theo Walcott, on as a half-time substitute for Van Persie, flashed a 25-yard drive just wide, and then Emmanuel Eboue had a shot cleared off the line by Fabio Aurelio.
And when, with 19 minutes remaining, Arsenal did finally breach Liverpool's defences, they were thwarted by one of their own.
Adebayor chipped in a cross towards Nicklas Bendtner and when Reina flapped the ball clear, Fabregas jabbed goalwards.
The ball was going in, only for Bendtner, in an offside position, to get in the way; had he simply got out of the way he would presumably have been judged to have not been interfering and the goal would have stood.
Fabregas went close with a late header but Arsenal could not find a second goal. The Gunners now face an uphill task at Anfield next week.
"We are playing at Anfield and we have shown that we can do special things there," said Kuyt.
In Tuesday's quarterfinal ties, Manchester United won 2-0 away to Serie A side Roma and Schalke 04 of Germany went down 0-1 at home to Barcelona.
The return legs are April 8 and 9.