Roma fielded a second-string side, but were humiliated 4-1 away to Celta Vigo in their final pre-season friendly.
Coach Eusebio Di Francesco concluded the mini-tour of Spain with massive changes just two days after their 2-1 defeat to Sevilla.
It was a truly disastrous start to the match at the Estadio Balaidos, as Lukasz Skorupski was kept busy by Guidetti, then Federico Fazio’s double howler saw him bring down Guidetti for a penalty converted by Iago Aspas.
Pione Sisto took centre-stage with two goals in five minutes, first dribbling away from two midfielders to unleash an absolute screamer, then making the most of a Bruno Peres error to spring the offside trap.
Aspas also completed his brace, finding a gap in the leaky Roma defence to tap in a low drive.
Di Francesco made more adjustments after the break and did get one back when Radja Nainggolan won back possession and Edin Dzeko knocked it down for Kevin Strootman’s stop and strike.
Goalkeeper Alisson had to prevent a fifth Celta Vigo goal with his save on Iago Aspas.
Celta Vigo 4-1 Roma
Iago Aspas 17, 42 (C), Sisto 22, 27 (C), Strootman 61 (R)
Celta Vigo: Sergio Alvarez; Mallo (C), Cabral, Fontas, Jonny; Wass, Radoja, Jozabed; Iago Aspas, Guidetti (Maxi 17), Sisto
Roma: Skorupski (Alisson 46); Bruno Peres (Nura 84), Fazio (Moreno 74), Juan Jesus (Castan 84), Kolarov (Manolas 46); Gerson (Strootman 46), Gonalons (Sadiq 84), Pellegrini (Nainggolan 46); Ünder (Tumminello 62), Defrel (Dzeko 46), Iturbe (Perotti 46)