The Swans could not continue their recent upturn in form on the south coast where they would suffer their heaviest defeat of the season.
Not much could be taken from the loss as Portsmouth picked up their fourth win in five games at home to move out of the relegation zone, whilst the Swans drop to 12th.
Ex-Cardiff winger Josh Murphy’s crisp first-time finish gave the hosts the lead midway through the first-half, before playmaker Paddy Lane poked home a second minutes later to give Portsmouth a 2-0 lead similar to that just over a month ago in south Wales.
The Swans briefly threatened to mount a comeback after the break, with full back Josh Tymon going closest rattling the woodwork, but centre back Ryley Towler’s header eased Portsmouth nerves and any chance of a Swans comeback.
It would get worse for Williams’ side as Cyrus Christie’s dreadful back pass compounded a miserable afternoon for the Swans allowing forward Colby Bishop to nip in to wrap up a comprehensive win.
“It was a very bad day at the office. If we want to be a better team, then we have to find a level of consistency, said Williams after the match.
“It is a really tough one to take. We didn’t compete and we struggled to get to grips with the conditions and opposition.
“We looked like we were lacking focus and concentration, and we got punished for that.
“This is where we are, we aren’t ready to consistently perform in a certain way, we aren’t there yet.
“If we want to be a better team we need to find a level of consistency.”
[Lead image: Swansea City FC]
