Eddie Nketiah’s brace after Elneny’s opener ensured Arsenal got a date with Manchester City in the FA Cup fourth round.
Nketiah, who has stepped up in the absence of injured striker Gabriel Jesus, has now found the back of the net five times in his last six matches and four goals in four consecutive starts for the Gunners.
Arsenal boss Mikel Arteta, while speaking after the game, believes Eddie Nketiah is getting better and better after helping the Gunners overcome Oxford United with three unreplied goals at the Kassam Stadium.
The Premier League leaders were frustrated in the first half by a well-organised and disciplined Oxford side before eventually overpowering their League One opponents.
There was some concern for Arsenal before Sunday’s North London derby with Tottenham when Bukayo Saka went off with an injury, but Arteta played down the seriousness of it.