Middlesbrough produced another FA Cup shock to extend Tottenham's long wait for silverware with a 1-0 win after extra time at the Riverside on Tuesday, while Manchester City eased into the last eight with a 2-0 victory at Peterborough.
Manchester City manager Pep Guardiola said he was happy with the Jack Grealish's contribution.
Tottenham Hotspur joined Chelsea in round four by beating Aston Villa 2-0, but Liverpool face a replay after being held 0-0 by Plymouth
Gayle, 22, joins Palace on a four-year contract after a season in which he scored 20 times for Peterborough and third-tier Dagenham and Redbridge, with whom he turned professional only 12 months ago. "I'm ecstatic really. I just want to get pre-season started now," Gayle told the Palace website.