Barcelona have earned a spot in the quarter-finals of the Copa del Rey but their continued participation in the tournament is still under threat.
Lionel Messi and Ousmane Dembele led Barcelona to a comfortable 3-0 win over Levante at Camp Nou Stadium on Thursday, helping them advance 4-2 on aggregate.
However, the Catalan club could be disqualified for allegedly using a suspended player in the first leg.
Levante say they will make a formal complaint to the Spanish football federation on Friday before the draw for the quarter-finals.
The four-time defending Copa champions have denied any wrongdoing for using youth player Juan "Chumi" Brandariz in last week's match in Valencia.
Levante says Chumi shouldn't have played because of an accumulation of yellow cards with Barcelona's "B" team, arguing his suspension applied to the senior team as well, including in Copa matches.
The Spanish federation is expected to rule on Levante's complaint before Friday's draw.
With Messi back in the line-up after being rested in the first leg, Barcelona easily reversed the 2-1 deficit from the first match.
The Argentine playmaker set up goals by Ousmane Dembele in the 30th and 31st minutes then sealed the victory by scoring in the 54th.
Barcelona have made it at least to the quarter-finals in the Copa in nine straight seasons. They won the title five times in the past seven years.
Earlier on Thursday, Espanyol defeated Villarreal 3-1 at home with two goals by striker Borja Iglesias to advance 5-3 on aggregate, while Real Betis salvaged a 2-2 draw at Real Sociedad to reach the last eight on away goals after a 0-0 first-leg draw.
Real Madrid, Girona, Valencia, Getafe and Sevilla also made it to the quarter-finals.