Boro’s solid, if unspectacular start to the top-flight season was ravaged by a free-flowing Reds outfit who claimed a 3-0 away victory.
The Merseyside club thus became the first visiting side to score three times at the Riverside Stadium since Sheffield Wednesday in August 2014.
In the process, Jurgen Klopp’s high-fliers made a mockery of Boro’s much-vaunted back-four, who had conceded just 16 times in 15 league games prior to the midweek action.
It made for a tough and ultimately “embarrassing” night according to Gibson, who pulled no punches following the setback, which represented far from ideal preparation for tomorrow’s ‘six-pointer’ with fellow strugglers Swansea.
Gibson said: “They (Liverpool) are a fantastic team. No one has cut us open like they did for a long time.
“We are really disappointed, and there are a lot of lessons for us to learn. That is the harsh reality of the Premier League.
“It is alright saying that you are going to get punished against the likes of Watford or Crystal Palace if you are not quite at the top of your game. But if you are not quite at the top of your game against a Liverpool or an Arsenal, you are going to get embarrassed.
“We have to learn the harsh lessons we have been taught and make sure it doesn’t happen again.”
Admitting the defeat was felt particularly painfully by Boro’s backline, Gibson added: “We have been really tight, so it is horrible when you have a night like that.
“As defenders, keeping clean sheets is our bread and butter. To concede at any time is painful – to concede three, especially at home, is not very nice at all.
“We played against a fantastic team and we were outclassed really.”