The Baggies were unbeaten heading into the Brighton clash, with a couple of wins and a draw, but they left the Amex Stadium on the wrong end of a 3-1 scoreline.
Boss Tony Pulis shouldered the blame for the defeat before putting his charges through their paces on Tuesday to ensure they are ready to face West Ham at the Hawthorns on Saturday.
Foster confessed that there were a few aching limbs after training as the squad came to terms with their underwhelming display on the south coast.
“It was a tough session,” he said. “In fairness, Tuesday is always a tough session. I think everyone was a bit frustrated from Saturday, it was an out-of-character performance from everybody to be honest with you.”
And the 34-year-old custodian feels they have benefitted from an honest discussion on the match and will now move forward.
“We had a little team meeting on Monday and that’s literally all it was, a couple of minutes to say ‘try and put it behind us’,” he added.
“It’s always quite tough after the international break, we’ve got a lot of players who are here, there and everywhere all over the globe.
“And we’ve had quite a few new players come in and I think that shakes things up a little bit.
“Nobody came off the pitch with full marks, it was a disappointing day and it’s one best put behind us.”
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