Vladimir Petkovic felt Lazio did well to “grind out the result” against Legia Warsaw, but criticised the fans.
The Biancocelesti opened their Europa League campaign with a 1-0 victory at the Stadio Olimpico , decided by a Hernanes header.
In the other Group J game, Trabzonspor scraped a last-gasp 2-1 win away to Apollon Limassol.
“Winning a game with the mind more than the quality of our play is very important, as during a season you must learn to hang on tight under pressure to grind out a result,” the Coach told Sky Sport Italia.
“It’s certainly good to keep two consecutive clean sheets. I was not worried when we made certain individual errors against Juventus, as aside from those meetings we conceded one goal in four games.
“Other clubs have taken players whose names make more noise, but we have a good squad and I was able to rest several of our internationals today. They are doing specific fitness training that we hope can bring us results.
“It was a shame that there were so few people today, as the team deserves a bigger crowd for its Europa League debut.”
This evening Lazio gave teenage talent Keita his full debut and the former Barcelona youth team prodigy provided the decisive assist.
“An 18-year-old can be a little nervous at the start of the game, but as time went on he gained in confidence and I am pleased he ran all the way up the field to set up the goal.
“Konko has tactical intelligence, while Cavanda is improving and slowly getting back on form after missing a few games. Everyone needs to keep on improving and doing better each time.”
Lazio face Roma in the Derby della Capitale on Sunday afternoon and Petkovic urged calm.
“We must all help calm the situation around the Derby by focusing on positives and trying to ignore the more negative sides of the build-up.”
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