Shaun Wright-Phillips grabbed his first goal for Chelsea as the Premiership champions came from a goal down to draw with the champions of Scotland.
Wright-Phillips (right) has struggled to make his mark at Chelsea
Gary Caldwell put Celtic ahead from close range from a corner kick.
But Wright-Phillips levelled before the break, cutting in from the left and unleashing a fierce low shot.
Andriy Shevchenko and Michael Ballack came on for the Blues in the second half and Shevchenko was denied a winner by a fine save from keeper Artur Boruc.
Kenny Miller went close for the visitors before the break while former Chelsea midfielder Jiri Jarosik also saw a header go just over the bar.
Salomon Kalou, Mikel John Obi and goalkeeper Hilario all made their first appearances at Stamford Bridge since signing for the club in the summer.
Celtic manager Gordon Strachan, who had rested some of his first-choice players, said the draw was a boost following Sunday's 2-1 defeat by Hearts.
"We might have made ourselves tired by taking on a game in midweek, but we have re-energised our minds and are feeling good about ourselves again," he said.
"We're not the richest club in the world, so we have to play games like this to bring in revenue."