Stephen Kenny was without Seamus Coleman and James McCarthy, and lost John Egan in the opening 15-minutes after a clash of heads.
The home side took the lead in the 18th-minute, after Harry Maguire rose highest to head home a Harry Winks cross at the back post. England doubled their lead on 31-minutes courtesy of Jadon Sancho’s shot into the bottom right corner.
England’s third came from the penalty spot ten minutes after the break. Cyrus Christie fouled Bukayo Saka, and Dominic Calvert-Lewin converted from the spot, to seal the win.
Ireland now travel to Cardiff, where they meet Wales in the UEFA Nations League on Sunday.
England: Nick Pope (Dean Henderson 46); Reece James, Michael Keane, Harry Maguire, Tyrone Mings (Ainsley Maitland-Niles 61); Mason Mount (Jude Bellingham 73), Harry Winks; Jadon Sancho, Jack Grealish (Phil Foden 61), Bukayo Saka; Dominic Calvert-Lewin (Tammy Abraham 63)
Republic of Ireland: Darren Randolph; Cyrus Christie (Kevin Long 60), Shane Duffy (capt), John Egan (Dara O’Shea 14), Matt Doherty; Jeff Hendrick, Conor Hourihane (Jayson Molumby 71); Daryl Horgan (James McClean 60), Alan Browne, Callum O’Dowda (Robbie Brady 60); Adam Idah (Ronan Curtis 71)