Saint-Etienne 1 Paris Saint-Germain 3: Blanc's men on track to retain Coupe de France
Holders Paris Saint-Germain bounced back from their long unbeaten Ligue 1 run ending at the weekend with a 3-1 Coupe de France quarter-final victory at Saint-Etienne.
Having seen their 36-game undefeated league streak come to a halt against Lyon on Sunday, PSG responded by taking an early lead at the Stade Geoffroy-Guichard, Zlatan Ibrahimovic playing a superb throughball to free Edinson Cavani for a simple finish.
Both strikers were also involved in PSG's second goal, Cavani helping on an Ibrahimovic cross to Marquinhos, who applied the finishing touch past Stephane Ruffier.
Saint-Etienne grabbed a goal back just before the interval when Valentin Eysseric converted a penalty after Layvin Kurzawa ended Kevin Malcuit's driving run.
But Lucas Moura added a third in stoppage time as PSG booked a semi-final spot that means Laurent Blanc's men, who have now beaten Saint-Etienne for a fourth time this season, remain firmly on track for a successive domestic clean sweep.
PSG travelled without Marco Verratti and Angel Di Maria, while Saint-Etienne had Jean-Christophe Bahebeck and top goalscorer Romain Hamouma unavailable.
Ibrahimovic had the game's first sight of goal after six minutes, but the striker could only head Cavani's cross wide of the target.
The pair linked up again for the opener after 12 minutes. Ibrahimovic screwed a reverse throughball into Cavani's path and he made no mistake, beating Ruffier with a placed finish.
A Kevin Monnet-Paquet strike was easily saved by Salvatore Sirigu after 23 minutes before Eysseric saw the PSG goalkeeper off his line and hit a long-range effort off target.
The visitors doubled their lead after 35 minutes following sustained pressure when Ibrahimovic's low cross was touched on by Cavani, Marquinhos just about staying onside to tap in at the far post.
Saint-Etienne were given a lifeline shortly before half-time when a clumsy Kurzawa challenge brought down Malcuit in the box, Eysseric sending Sirigu the wrong way from the penalty spot.
The hosts then came close to an equaliser after 58 minutes when Eysseric forced Sirigu into another save.
The woodwork denied Blanc's men when Blaise Matuidi found Javier Pastore in space, but the winger's powerful drive thundered back off Ruffier's post.
Ibrahimovic, who had previously scored 14 goals in 12 games against Saint-Etienne, saw an effort kept out by Ruffier's leg before substitute Nolan Roux flashed a header onto the roof of the net at the other end.
It was left to Lucas to crush home hopes after beating three defenders on a brilliant solo run.