Chelsea produced a composed performance to secure a fully deserved draw and a crucial away goal to put themselves in a promising position after their Champions League semi-final first leg against Real Madrid.
Thomas Tuchel's side were superior on the night and might even regard themselves as unfortunate not to take an advantage into the return at Stamford Bridge in eight days' time as they set their sights on a final date against either Manchester City or Paris St-Germain in Istanbul on 29 May.
Chelsea over-ran Madrid in the early stages and should have taken the lead when Timo Werner shot straight at keeper Thibaut Courtois from only six yards - but they were ahead after only 14 minutes when Christian Pulisic kept his cool to steer home a clever finish.