Rangers on the cusp of quarter-finals with big win
These teams will try again in Istanbul next week, with a quarter-final place at stake, and Barcelona could rue the opportunities they missed in this contest.
Xavi was an unused substitute when these teams last met, in the 2002-03 Champions League, but here he was orchestrating from the bench as head coach.
Barcelona almost snatched the lead with a freakish goal, when an overhead kick from Pierre-Emerick Aubameyang was going well wide before Frenkie de Jong instinctively flung out a leg and volleyed against the left post, but it was not to be their night.
The host wanted an early penalty when Adama Traore's cross hit the arm of Kerem Akturkoglu but had to settle for a corner. Memphis Depay then tested Galatasaray goalkeeper Inaki Pena – on loan from Barcelona – with a fiercely struck free-kick from 22 yards in the 27th minute, the first shot on target in the contest.
This incarnation of Galatasaray sit only 12th in the Turkish Super Lig, a pale shadow of their great teams, but they almost had a goal to rank among their finest in Europe.
A slaloming, bustling run down the left by Akturkoglu, starting deep inside his own half, ended with a dart into the penalty area and a shot from 15 yards being deflected inches over for a corner by Eric Garcia.
Barcelona made three changes for the start of the second half, Xavi looking to jolt his team as he withdrew Ronald Araujo, Nico and Ferran Torres, bringing on Gerard Pique, Sergio Busquets and Ousmane Dembele.
Busquets had a header tipped over and home captain Jordi Alba cracked a powerful right-footed volley a foot wide of the left post, before De Jong almost put away Aubameyang's wayward effort.
Galatasaray thought it had snatched a winner against the run of play through Bafetimbi Gomis, as the striker smashed past Marc-Andre ter Stegen, but he had strayed offside.