Chelsea booked their place in the FA Cup final after securing a 2-0 victory over Southampton in the semi-final at Wembley Stadium on Sunday afternoon.
Antonio Conte selected Giroud over Morata in attack and the French forward rewarded that faith with the opening goal in the first minute of the second half.
Cesc Fabregas and Eden Hazard combined superbly to find Giroud in the box but he still had a lot to do, jinking away from a series of challenges before prodding past Alex McCarthy.
Shane Long wasted a golden opportunity to grab a leveller for Mark Hughes’ men, the Southampton striker’s heavy first touch preventing him getting a shot on goal, while he also saw a penalty shout turned away by referee Martin Atkinson.
Conte’s tactical nous has been questioned in what has been a difficult season but his decision to replace Giroud with Morata with 10 minutes to go proved a masterstroke, Morata heading in a Cesar Azpilicueta cross 88 seconds after his arrival.
The win sees Chelsea advance to a meeting with Manchester United on May 19 and the chance to avenge last year’s defeat to Arsenal in the Wembley showpiece.
Hazard, looking refreshed after being left out of the starting XI for Thursday’s win at Burnley, rifled just over the angle in the fifth minute as Chelsea started on top.
The Belgium winger then drove through the centre of the pitch, teeing up Willian to crack an effort against the top of the crossbar.
Willian’s 14th-minute free-kick was too high to worry McCarthy and Mario Lemina failed to seriously test stand-in goalkeeper Willy Caballero with a hopeful strike at the other end.
Fabregas was running the midfield and, when Giroud flicked his chipped cross into the air, the striker twisted to direct an acrobatic volley wide of the post.
Giroud – who scored twice from the bench in a comeback Premier League win at Southampton last weekend – found the net 27 seconds into the second half, though.
Another cute Fabregas ball into the box was plucked out of the air by Hazard, who regained balance and composure to play in Giroud, the target man brilliantly dribbling past three Southampton defenders before stabbing home.
Southampton had barely threatened but Long found himself through on Caballero’s goal after Charlie Austin dummied Wesley Hoedt’s pass, the striker’s control badly letting him down.
Atkinson rejected Long’s weak penalty appeals and there were boos from the Chelsea fans for Conte’s decision to bring on Tiemoue Bakayoko in place of Willian, who walked straight down the tunnel.
Former Chelsea player Hughes introduced attacking duo Nathan Redmond and Dusan Tadic in the 63rd minute in search of an equaliser, Caballero brilliantly denying the English winger with his legs.
But it was a Chelsea change that proved decisive, Morata heading home his third goal of 2018 from a precise Azpilicueta centre, although Charlie Austin almost pulled one back only to be denied by the post.
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