Tony Pulis admitted West Brom were second-best throughout their 3-0 defeat by Southampton.
Two goals from James Ward-Prowse and a second-half strike by substitute Dusan Tadic made it a comfortable afternoon for the Saints, as West Brom slipped to their fourth away league defeat of the season.
Pulis felt his side could have had a penalty for a first-half challenge on Craig Gardner, but offered no excuses for a "flat" performance at St Mary's.
"We conceded a poor goal after five minutes and it never got any better for us," Pulis said. "We needed the break and we could have had a penalty after 25 minutes.
"I've not seen it but Gardner has said it was a penalty. He's quite an honest lad but I'm not taking anything away from Southampton, they were the better team and deserved to win the game without question."
The Baggies earned a 2-2 draw at Chelsea in midweek, and sought to minimise their travel time between back-to-back away games by arriving in Southampton on Thursday.
Pulis made three changes, and despite ending the game with Saido Berahino, Salomon Rondon and Victor Anichebe in attack, West Brom failed to test Southampton goalkeeper Fraser Forster in a lethargic performance.
Darren Fletcher also added to the manager's injury concerns after limping off at half-time, and they face a quick turnaround at Bristol City in an FA Cup third-round replay on Tuesday night before hosting Aston Villa next weekend.
"We've got another two games coming up next week," Pulis added. "Obviously we lost James Morrison at Chelsea and we've lost Fletcher today, who had to come off at half-time. He has opened up his knee a little bit.
"It's injuries that you don't want to pick up and injuries to important people.
"The interesting facts would be to look at this time of year and having to play two games in a week, and seeing how many other teams had to play their second game away from home and actually picked up results.
"We tried our best to give the lads as much rest as we possibly could. We planned it that way, and you're hoping it works but we were flat. There's no excuse."