The Tigers slumped to a fifth reverse in seven games away from the KC Stadium since the turn of the year, a run that has seen Steve Bruce’s men score just twice.
Once again individual blunders cost Hull dear as Swansea were gifted two first-half goals.
While Hull did show commendable spirit after half-time, particularly when reduced to 10 men following David Meyler’s 53rd-minute dismissal, McShane believes there has to be a huge improvement if Yorkshire’s sole top-flight representatives are to remain clear of trouble.
“It is worrying when you are down there like us,” said the Republic of Ireland international, whose goal just after the break was his first in the Premier League since 2008.
“There are lots of twists and turns in the last few weeks. But this has to be a massive wake-up call.
“It seems we need to go 2-0 down to start playing. That is not great. We did the same against Chelsea (two weeks earlier).
“We were 2-0 down then and the pressure was off because the game was nearly gone. It just wasn’t good enough in the first half.”
Results elsewhere hardly helped Hull’s cause, as while they were slipping to defeat in south Wales both Leicester City and QPR were claiming unlikely victories.
And yesterday, Burnley gained a point in a goalless draw with Spurs while Sunderland took all three points in the Wear-Tyne derby, beating Newcastle 1-0.
All in all, therefore, a worrying predicament for the Tigers, who have a devilish run-in that includes meeting five of the top seven.
McShane added: “It doesn’t matter who we play, we need points – and we have proved many times that we can get points off the big boys.
“We have had some good results away from home and we should have got something off Chelsea.
“Every year is the same in that teams start putting runs together. People get dragged in, as a result.
“Swansea wasn’t good enough and we have to realise we are fighting for every point. It can’t take 2-0 down to get us going. We have to start better.”
Defeat was made particularly hard to take for the hardy band of Tigers fans who embarked on the marathon journey to Swansea on Saturday by the manner in which the damage was self-inflicted.
Not for the first time this term, Allan McGregor was culpable, for the opening goal on 19 minutes.
Jonjo Shelvey’s 20-yard shot was well struck after the visitors failed to close down the midfielder quickly enough, but it was close enough to the Scot to make a save and, in the process, push the ball away from danger.
Instead, though, McGregor could only divert the shot into the path of the impressive Ki Sung-Yueng and he did the rest with a first-time finish.
Considering there had not been a shot on target at that stage of the afternoon, Hull had paid a big price for switching off.
It was a similar story for the second goal eight minutes before half-time, as Robbie Brady and Alex Bruce got in an almighty tangle when both trying to head clear.
All the pair did was present Bafetimbi Gomis with a difficult chance that he made look easy with an acrobatic scissor-kick that gave McGregor no chance.
As had been the case in their previous outing at home to Chelsea, the Tigers were two goals down and looking shell-shocked.
Just like against Jose Mourinho’s men, however, a rally was staged with McShane finishing from close range four minutes into the second half after Bruce had flicked on Brady’s free-kick.
Suddenly, the visitors were transformed into a cohesive attacking unit as Michael Dawson had a header deflected wide and Lukasz Fabianski had to drop on the ball bravely amid an almighty scramble.
Even the dismissal of Meyler for a reckless challenge on Kyle Naughton could not disrupt Hull, who really should have equalised on the hour.
Dame N’Doye, moved out towards the left, provided the cross that found Abel Hernandez eight yards out. A sweet connection and Hull would have been level. Instead, the club’s record £10m signing could only manage a fresh-air shot as the ball ran to safety.
It proved to be the Tigers’ last chance of salvaging anything from an afternoon in which, despite the second-half improvement, they simply carried too many passengers.
Swansea netted a third in stoppage time when Gylfi Sigurdsson played Gomis clear and he finished coolly past McGregor.
Swansea City: Fabianksi; Naughton (Rangel 56), Williams, Fernandez, Taylor; Routledge, Cork (Dyer 65), Ki, Shelvey (Grimes 89), Sigurdsson; Gomis. Unused substitutes: Amat, Emnes, OIiveira, Tremmel.
Hull City: McGregor; McShane, Bruce (Diame 70), Dawson; Elmohamady, Meyler, Livermore, Ramirez (Quinn 30), Brady; Hernandez (Aluko 81), N’Doye. Unused substitutes: Sagbo, Chester, Harper, Rosenior.