PSG appeared to be cruising towards a commanding first leg lead in their UEFA Champions League last-16 encounter, with Ezequiel Lavezzi and Javier Pastore having netted two crucial away goals.
A dramatic end to the game has threatened to turn the tie on its head, though, with Adil Rami grabbing a late reply for Valencia and Ibrahimovic picking up a red card which will see him suspended for the return date at Parc des Princes.
"We conceded a goal and we took a red card. We didn't deserve this because it was a normal tackle," Ancelotti told Sky Sports.
"We are really disappointed because the rest of the day was really good, we played really well and were focused on the game. For that we have to be happy, but the end of the game was not good for us.
"Valencia is a good team. We have to know that we have just played the first half of this game and we have to play the second half at home. I think that will be better for us, but we have to pay attention."
On the decision to dismiss Ibrahimovic for a challenge on Andres Guardado, Ancelotti added:"I think it was a normal tackle, nothing special and I was surprised with the red card."
David Beckham, who has signed a five-month contract with PSG, was an interested spectator at the Mestalla on Tuesday and Ancelotti is looking forward to welcoming the former England captain into his ranks for the remainder of the season.
He said: "He doesn't have a problem. He trained one week alone and tomorrow we start with his team-mates. I think he doesn't have a problem to play and I'm sure he will help us to do better."
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