Chelsea have a 1-0 half-time lead over Basel in the first leg of their Europa League semi-final in Switzerland.
The visitors took the lead in the 12th minute as Victor Moses got the final touch on Branislav Ivanovic's header from a corner.
Basel responded well to going behind and they forced a save from Petr Cech midway through the half when the goalkeeper was forced to tip Fabian Schar's deflected effort over the crossbar.
The hosts continued to push and they hit the woodwork on 28 minutes as Valentin Stocker's cross clipped the post before going out of play.
However, Chelsea came close to extending their advantage late on when Ramires was put through on goal by Frank Lampard before seeing his clipped shot kept out by Yann Sommer.
