Pedro scored with a header in extra time for Chelsea to advance to the FA Cup semifinals with a 2-1 win at Leicester on Sunday.
Chelsea next faces Southampton at Wembley Stadium after new manager Mark Hughes' side beat Wigan 2-0.
Manchester United plays Tottenham in the other semifinal, which is also at Spurs' temporary Wembley home.
Chelsea was made to work hard to progress in the only remaining competition it can win this season. Alvaro Morata got the visitors going with his first goal of the year.
The Spanish striker scored on a counterattack minutes before the break. Willian won the ball near his own penalty area and found Morata with a fine pass. Morata took one touch and then sent the ball over the outrushing Kasper Schmeichel with a fine finish.
Leicester improved after the interval and Jamie Vardy might have equalized when he headed a good opportunity over.
The home side's pressure finally paid off when Vardy equalized with a quarter-hour remaining. Riyad Mahrez crossed and Vardy's initial effort was blocked by a defender, as was Vicente Iborra's attempt. Chelsea goalkeeper Willy Caballero saved Iborra's follow-up, before Vardy finally scored at the fourth attempt.
Caballero, playing in place of the injured Thibaut Courtois, saved another effort from Vardy with minutes remaining, before Schmeichel denied Morata at the other end to send the game to extra time.
However, the Leicester goalkeeper failed to claim N'Golo Kante's cross and Pedro was allowed to head in the winner during the first half of extra time.
SOUTHAMPTON WINS WITH HUGHES
Southampton rallied after halftime to defeat third-tier Wigan 2-0 and reach the semifinals in Mark Hughes' first match in charge.
Hughes, who took over as coach from the fired Mauricio Pellegrino on Wednesday, watched as his side was largely outplayed by the home team in the first half. Wigan knocked Manchester City out in the previous round and was looking to beat its fourth Premier League side.
But the visitors improved in the second half and Pierre-Emile Hojbjerg made the breakthrough in the 62nd minute when he converted a corner at the near post. The Danish midfielder had just forced a good save from Wigan goalkeeper Christian Walton from the previous corner, and Walton had prevented Manolo Gabbiadini from opening the scoring minutes earlier.
Gabbiadini had the chance to make it 2-0 from the penalty spot with just under 20 minutes remaining, but Walton saved his spot kick.
Portuguese right back Cedric finally sealed the win on a counterattack in injury time.