Reiss Nelson’s goal sent Arsenal into the fourth round of the FA Cup after Leeds failed to capitalise on a dominant first-half display at the Emirates Stadium.
The Sky Bet Championship leaders were outstanding before the break, showing their Premier League credentials as they attempted 15 shots to Arsenal’s three and registered more than 60 per cent possession, but their wastefulness was punished when Nelson struck soon after half-time.
The 20-year-old, one of only two youngsters in an experienced Arsenal line-up along with Matteo Guendouzi, converted from close range after Nicolas Pepe and Alexandre Lacazette had combined on the right-hand side.
Arsenal dominated the rest of the second half and missed chances to extend their lead further, with substitute Gabriel Martinelli forcing a fine one-handed save from Leeds goalkeeper Illan Meslier, but the 1-0 scoreline was enough to set up a fourth-round tie away to Bournemouth.
Arsenal: Martinez (8), Sokratis (7), Luiz (7), Holding (5), Kolasinac (6), Xhaka (6), Guendouzi (6), Nelson (7), Ozil (7), Pepe (7), Lacazette (7)
Subs: Martinelli (7), Willock (6), Saka (n/a)
Leeds United: Meslier (8), Ayling (7), White (7), Berardi (7), Douglas (6), Phillips (8), Harrison (7), Gotts (7), Klich (6), Alioski (7), Bamford (7)
Subs: Dallas (7), Costa (6), Stevens (6)
Man of the match: Emiliano Martinez