Claudio Ranieri warned his Leicester City players to expect a tougher season after the Premier League champions were defeated 2-1 by Hull City.
Robert Snodgrass scored what turned out to be the winner for the Tigers in the early kick-off at the KCOM Stadium on Saturday.
Adama Diomande put the home side ahead with a wonderful overhead kick but his effort was cancelled out two minutes later by a Riyad Mahrez penalty.
The defeat meant Leicester - who lost just three league games last season - became the first Premier League champion to lose the first match of their title defence.
Speaking to Sky Sports' Geoff Shreeves after the defeat, Ranieri warned of a tougher campaign than last season's fairytale.
"I told my players this season this season will be harder than the last season because sometimes we played well and you can lose the match," the Italian said.
"Today was a normal match, maybe a draw was normal but we lost the match. For this reason I told [the players] we must be very, very strong together because we showed [we are] a very good team last season and we have to repeat."
The Foxes dominated possession but found themselves come up against a spirited Hull. Jamie Vardy spurned a decent first-half volley and Ranieri criticised his side's profligacy in front of goal.
"I think we lost two great chances to score and then we were more and more smart at plays. We lost after we lost the ball and they made a goal," he added.
"We made a lot of effort but not as a team. They defended very well and tried to play counter- attacking and played well."
Wes Morgan said his Foxes team mates were second best across the pitch and Ranieri agreed with his captain.
"Yes, I think so. They played better. We tried to do our best, the effort was amazing but [it was] individual effort, not as a team. I think this was they key to the match.
"We came here to try to win as we are used to do. Sometimes it is not possible and of course we make some mistakes and then we had to think where we made mistakes."
Leicester will be hoping to kick-start their title defence when they take on Arsenal next Saturday while Hull travel to Swansea on the same day.