Brian McDermott felt Reading paid the price for a slow start in their defeat by Tottenham Hotspur.
The 2011/12 Championship winners remain without a victory since returning to the Premier League after Sunday's 3-1 loss at the Madejski Stadium.
Andre Villas-Boas' previously-winless Tottenham dominated for the majority and scored their goals through Jermaine Defoe in the 18th and 74th minutes either side of a 71st minute Gareth Bale effort.
Relegation-zone occupants Reading pulled back a 90th minute consolation through substitute Hal Robson-Kanu.
But McDermott was left to rue a disappointing first half, which had seen him replace Jem Karacan with Adam Le Fondre at the interval.
The Reading boss told Sky Sports 1HD: "I did not recognise us in the first half. I thought we were too submissive, did not get on the ball enough, did not get in their faces.
"We had to make the change in the second half and I thought we were better for 20 minutes. The second goal killed us, really.
"We know we have come up against a top-class side. They played well today and deserved to win."
Next up for Reading is a league trip to West Bromwich Albion, a Capital One Cup visit to Queens Park Rangers and then a home top-flight game against Newcastle United at the end of September.
And McDermott will be demanding improvements from his side if they are to avoid a season-long battle with relegation.
"It is a learning curve for all of us," he said. "We know we are playing against a team which is full of world-class individuals.
"Today, they have played well. But we did not cause them enough problems, especially in the first half.
"We cannot have performances like we had in the first half and expect to win. If we do what we normally do and what we are capable of, we will give ourselves a chance."