Marcos Alonso struck late to earn Chelsea a 1-0 at Europa League quarterfinal opponents Slavia Prague.

The Spaniard timed his run perfectly to meet Willian's right-wing cross with a firm header four minutes from time in the Czech capital.

Maurizio Sarri's under-strength side struggled to find any rhythm for large spells, but grew into the game after Eden Hazard was introduced off the bench just before the hour mark.

The second leg at Stamford Bridge takes place on 18 April.