Ralph Hasenhuttl says Southampton's high-intensity tactics are being undermined by a lack of fitness among his rusty players.
Saints were dumped out of the Carabao Cup by Championship club Brentford on Wednesday evening after starting the new Premier League season with a disappointing loss at Crystal Palace.
Manager Hasenhuttl has a relatively small squad at his disposal and been frustrated by the limited time to prepare during a pre-season cut short due to the prolonged 2019-20 campaign.
The Austrian, who fielded a full-strength side for the 2-0 defeat to the Bees, favours a vigorous pressing style and concedes it is impossible to effectively implement that gameplan given current circumstances.
"We don't want to lie to ourselves. We want to see very clear how we are," said Hasenhuttl.
"In the moment we are by far not that good as we have been last season.
"There are some reasons why: we had no pre-season, we had no time to work together. We had definitely physically a different level when we came back after lockdown.
"We are out of position at the moment. Our game is very intense, we need to have fit players. In the moment, we are not fit enough.
"It seems we have problems in a few parts of our game and this can cost you always points and wins."
Southampton were among the top-flight's form teams at the end of last term, taking 18 points from nine post-lockdown fixtures.
They offered little sign of a comeback against Brentford after conceding first-half goals to Christian Norgaard and Josh Dasilva.
Hasenhuttl had hoped to use the cup competition to sharpen his out-of-shape players but is now resigned to doing that work on the training field following a surprise second-round elimination.
Saints host Jose Mourinho's Tottenham on Sunday lunchtime followed by a fixture-free week ahead of a trip to Burnley.
"It's about getting in the rhythm and getting automatism and getting physically stronger. I don't have the chance to train at the moment so I need the games to play," said Hasenhuttl.
"But we are out of the cup so we have maybe in the next weeks more time to train and to work together on our behaviours because in the moment, to be honest, we are far away.
"In the past, we were only competitive when we had all the players in the highest level and working together on our shape."