Willian is one of four players who return to the starting XI for the visit of Eintracht Frankfurt tonight.
The Brazilian replaces Pedro in attack and is joined there by Olivier Giroud, who leads the line, and Eden Hazard, not a starter in Germany a week ago.
With N'Golo Kante out injured, Ruben Loftus-Cheek returns in midfield alongside Jorginho and Mateo Kovacic. Emerson Palmieri for Marcos Alonso is the only change to the defensive unit.
For the visitors Ante Rebic returns from suspension. Gelson Fernandes makes way. Sebastien Haller, who missed the first leg through injury, is on the bench.
Chelsea (4-3-3): Arrizabalaga; Azpilicueta (c), Christensen, David Luiz, Emerson; Kovacic, Jorginho, Loftus-Cheek; Willian, Giroud, Hazard.
Subs Caballero, Zappacosta, Alonso, Cahill, Barkley, Pedro, Higuain.
Eintracht Frankfurt: Trapp; Abraham (c), Hasebe, Hinteregger, Da Costa, Rode, Gacinovic, Rebic, Falette, Jovic, Kostic.
Subs Ronnow, N'Dicka, De Guzman, Haller, Fernandes, Chandler, Paciencia
The referee is Ovidiu Hategan from Romania
Chelsea are the first English side to win 11 major European games in a single season.
Chelsea have reached 14 European semi-finals since April 1966 – seven in the Champions League, four the Cup Winners’ Cup, two in the Europa League and one in the Inter-Cities Fairs Cup.
This is our ninth major European semi-final appearance since Roman Abramovich became owner; no club has appeared in more since then (Barcelona also nine).
The Blues are now a record 16 games unbeaten in the Europa League, the draws at MOL Vidi and in Frankfurt being the only games in that sequence that we did not win. Our last defeat in the competition was 2-3 at Rubin Kazan in the 2012/13 quarter-final second leg after we won 3-1 at the Bridge.
Chelsea have won our past nine Europa League matches at Stamford Bridge by an aggregate score of 27-7.
We are undefeated in Europe over 13 matches, closing in on the club’s record unbeaten sequence of 14 UEFA competition matches between 2008 and 2010.
Chelsea have scored the most goals (31) and had the most shots (217) in the Europa League this season.
Chelsea have lost just one of our last 11 games against German sides in all European competitions (five wins, five draws).
The Blues have scored in each of our past 37 home games in European competition, netting 98 goals in the process (2.65 per game). The last occasion we failed to score was against Manchester United in the Champions League quarter-final in April 2011.
We have been involved in four penalty shoot-outs in European competition, winning in Munich in 2012 and losing the other three.