Charles proved there is life after Iago Aspas at Celta Vigo, but their problems were in defence and not attack as they let a two-goal lead slip in a 2-2 draw with Espanyol.
Aspas left the Balaidos to head to Liverpool over the summer and Charles was recruited from Almeria to plug the gap.
He made an immediate impact, scoring a second goal after Alex Lopez had opened the scoring, but the home side could not hold their lead.
In between some breathtaking goalkeeping from Francisco Casilla, they pulled one back from Victor Sanchez and then added a second through substitute Koulossa Thievy.
Elsewhere, Rayo Vallecano kicked off the new season with all three points by earning a comfortable 3-0 victory over newly-promoted Elche.
New signing Alberto Bueno got the opening goal after 40 minutes, Alberto Perea doubled the lead right on the stroke of half-time with a sensational strike, and Bueno wrapped up the points by adding the third with 16 minutes to go.
Both sides fielded radically different teams from last season following wholesale squad overhauls in the summer, but Rayo's players settled easier and controlled the game from start to finish.
Giovani dos Santos and Jonathan Pereira scored in the space of four second-half minutes as Villarreal twice came from behind to see off fellow promoted side Almeria 3-2.
On-loan striker Rodri scored in either half, in between Sebastian Dubarbier's own goal just after the hour which levelled proceedings, to put Almeria on course for the three points in their Primera Division opener.
But new signing Dos Santos levelled proceedings seven minutes from time before substitute Pereira sealed a dramatic victory for the Yellow Submarines soon after.
Information from the Press Association was used in this report.