Lionel Messi pounced after a mistake by Andreas Christensen to score a potentially crucial away goal for Barcelona in the Champions League last-16 first leg.
Willian, who hit the post twice in the first half, put Chelsea ahead shortly after the hour mark at Stamford Bridge.
Eden Hazard’s pass found Willian near the edge of the penalty area and the Brazilian shimmied to his right and smashed a low shot beyond keeper Ter Stegen and into the bottom corner of the net.
Earlier, Willian cut in from the left and fired against the woodwork.
He hit the post again with another strike four minutes before the interval and Hazard then volleyed narrowly over as Chelsea ended the first half on top.
Having looked mightily impressive while pinging the ball around in the early stages, Barca struggled to create clear-cut chances before Messi struck with 15 minutes remaining.
The goal came as a result of Christensen’s wayward pass to Cesar Azpilicueta.
Andrés Iniesta nipped in to nudge the ball away from his fellow Spaniard and then pull it back to the waiting Messi, whose left-footed finish leaves his side in a strong position going into the second leg.
Chelsea: Courtois; Azpilicueta, Christensen, Rudiger; Moses, Kante, Fabregas (Drinkwater 84), Alonso; Willian, Hazard, Pedro (Morata 83).
Subs not used: Caballero, Cahill, Zappacosta, Hudson-Odoi, Giroud.
This post was last modified on 21/02/2018