AS Roma manager Paulo Fonseca said he was unaware of a substitutions mix-up in Tuesday's Coppa Italia defeat by Spezia after making six changes when only five were allowed.
The sixth change came in extra time when Fonseca introduced defender Ibanez for former Chelsea winger Pedro, having already made five substitutions in the round-of-16 match at the Olympic Stadium.
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Roma, who also received two red cards in the space of two minutes, were beaten 4-2 after extra time.
When asked about the error, Fonseca told reporters: "If there was a problem, that I honestly didn't know about, we'll discuss it internally."
Italian FA rules state that teams can make five subs in three slots through the 90 minutes. Should a match go to extra time, teams have an extra slot so long as they have not already used their five subs.
Spezia had raced into a two-goal lead in the capital through an Andrey Galabinov penalty and Riccardo Saponara after 15 minutes.
Roma pulled one back through a Lorenzo Pellegrini penalty just before half-time before Henrikh Mkhitaryan equalised 13 minutes from the end to get the game to extra time.
But within two minutes of the restart, Roma were down to nine men. First, defender Gianluca Mancini received a second yellow card for a foul just inside his own half and, from the resulting free-kick, goalkeeper Pau Lopez tried to clear the ball, but completely missed his kick and took out Spezia's Roberto Piccoli instead and was dismissed.
Daniele Verdi's header put Spezia back in front in 107 minutes, but a stunning Saponara chip one minute from time confirmed the newly promoted side's place in the quarterfinals.
This defeat for Roma comes just four days after their humiliating 3-0 reverse in the local derby against Lazio.
Earlier in the season, Roma were handed a 3-0 defeat against Hellas Verona in Serie A for fielding an ineligible player.
Information from Reuters was used in this report