Claudio Ranieri admits he is concerned by Leicester’s poor defending so far this season.
The Premier League champions have already lost three times in the top-flight this term – the same amount of defeats they suffered during the whole of last season as they won a shock title.
They conceded four first-half goals in their 4-1 defeat at Manchester United on Saturday as the hosts netted three goals from corners.
Leicester welcome Porto to the King Power Stadium for their Champions League Group G game on Tuesday with Turkish official Cuneyt Cakir, who takes charge, having handed out 11 yellow cards and one red in his last two games.
Ranieri admitted his players are worried about conceding penalties after referees were told to clamp down on holding and grappling in the box but told them to go back to their old ways.
“Yes, we concede a lot of goals,” Ranieri said. “I spoke to the players and they were scared. What the referees speak about is not a new rule, it’s something we’re used to doing. I said ‘why change?’
“Last season we were one of the best in the league and conceded very few goals from the set pieces and now we leave four metres. We have to go back to our strengths.”
Leicester won their opening Champions League game 3-0 at Club Brugge two weeks ago as Porto drew 1-1 with FC Copenhagen.
But after their heavy defeat at Old Trafford the Italian conceded he was worried about their early-season form which also included a 4-1 loss at Liverpool.
He said: “Of course it’s a concern. Last season everything was perfect. This season, no. The first chance the opponents have, they score.
“I’m not happy when my teams don’t react. We can concede a goal but I want to see us react every time. I spoke to them and I am very sure they understood it all.”
Leicester’s record buy Islam Slimani scored five goals against Porto for former club Sporting Lisbon in 2016 and Ranieri hopes he lives up to his nickname of the ‘Dragon Slayer’.
Ranieri added: “He’s a goalscorer and has scored a lot of goals against Porto and I’m sure he’ll be a threat to them. Slimani scores so many times against Porto, I am thinking if he’s going to play or not!”
Porto won the Champions League in 2004 under Jose Mourinho but have lost 14 of their 16 games in England, drawing twice, and current boss Nuno Espirito Santo knows it must improve.
He said: “History tells us FC Porto has never managed to win in England but records are there to be broken. We have a chance in front of us.
“Leicester are champions of the Premier League and it is one of the best leagues in the world. What Leicester did last season is remarkable and we must respect it.”