The Viola moved level on points with fourth-placed Inter in Serie A after making hard work of beating 10-man Verona 4-3 in a classic match
The fifth-placed Viola moved level on points with Inter after beating the side sitting sixth in Serie A in a seven-goal epic.
The match, which included four goals in the opening 14 minutes, saw Borja Valero, Juan Vargas and Giuseppe Rossi score for Fiorentina, who made hard work of securing a victory despite playing much of the match against 10 men after Bosko Jankovic was sent off early in the second half.
"We should be more ruthless in defence and attack," Montella told Sky Sport Italia after the match.
"I have to give praise to our opponents but we cannot always score four times to secure a victory. In this game we had so many chances to extend our advantage going forward and at the back we have got to maintain our concentration better."
The coach was full of praise for Valero, who scored twice in a league game for the first time since March 2008, when he bagged a double for Mallorca in La Liga.
"If Borja Valero can start scoring from outside the box as well, then it is clear this is a complete player," concluded Montella.