Chelsea's Ross Barkley celebrates after scoring his side's opening goal during the FA Cup sixth round soccer match between Leicester City and Chelsea at the King Power Stadium in Leicester
Substitutes made the difference as Chelsea and Arsenal both won away from home to reach the FA Cup semifinals on Sunday.
Chelsea midfielder Ross Barkley turned in a cross from Willian midway through the second half in a 1-0 win at lackluster Leicester.
Spanish midfielder Dani Ceballos netted an injury-time winner in a 2-1 win at Sheffield United, which had two goals ruled offside by video replay. Ceballos pounced with a low shot, just four minutes after David McGoldrick had equalized from close range.
Later Sunday, Cup holder Manchester City was away to Newcastle.
At Bramall Lane, forward Nicolas Pépé's penalty put Arsenal ahead midway through the first half, after United midfielder John Lundstram had an early header ruled out for offside. United defender John Egan's header early in the second half was also chalked off.
Arsenal has won the FA Cup a record 13 times, one more than Manchester United — which squeezed into the semis with an extra-time 2-1 win against 10-man Norwich on Saturday.
In Sunday's only Premier League game, striker Danny Ings scored twice to reach 18 goals as Southampton won 3-1 at struggling Watford.
Ings struck in each half to move one goal behind top scorer Jamie Vardy, who is enduring a lean spell for third-place Leicester.
Southampton moved up one place to 13th and is a comfortable 13 points clear of the relegation zone. But 16th-place Watford remains one point above the drop zone with six games left.
