Mind you, it’s a lot more convenient to protest when the reasons for the dissent have shown little or no negative impact on the team itself, even though United’s ongoing success is being achieved, with one notable exception, by a group largely comprising players either past their best or yet to realise their full potential.

It underlines the sub-standard fare throughout Europe at present and brings into sharp focus the inability of Liverpool to build on last season’s title challenge.

Buoyed by two wins in four days, Benitez’s side couldn’t have wished for a better start yesterday when they went ahead on five minutes with an excellent goal.

Dithering from Michael Carrick on the halfway line gave Liverpool possession and, after Gerrard released Dirk Kuyt down the right, the Dutchman’s inch-perfect cross was met by the unmarked Torres to power a header past Edwin van der Sar.

However, that platform lasted only seven minutes when United drew level with a goal that could charitably be described as fortunate.

After Insua’s silly header back infield fell to the onrushing Valencia, the United winger was held by the tracking Mascherano just outside the area.

However, Valencia continued his run into the box before falling over, convincing referee Webb and his assistant to award a penalty.

With United cheekily claiming Mascherano should be dismissed – Jamie Carragher was a covering defender – Liverpool’s frustration boiled over as Torres foolishly scuffed the penalty spot.

To then add insult to injury, Rooney’s well-struck penalty was brilliantly saved by Pepe Reina only to fall straight back at the feet of the in-form striker – otherwise well marshalled by a Liverpool defence in which Daniel Agger was the pick – to tap home. Following that blistering opening, the rest of the game was a tetchy affair of few chances, the best in the first half falling to Park who sent a free header wide from Valencia’s cross. Liverpool, though, didn’t heed that warning, and on the hour Park again ghosted into the box unmarked to steer a stooping header beyond Reina from Darren Fletcher’s right-wing cross.

Torres couldn’t quite control Gerrard’s low cross as the visitors sought an instant response and, with passions rising, Fletcher was lucky to avoid censure after kicking out at Kuyt.

Benitez threw on Alberto Aquilani, Ryan Babel and Yossi Benayoun in the closing quarter, but Liverpool showed a curious lack of urgency and offered no serious threat until spurning a gilt-edged opportunity in the final minute of normal time.

Neat interplay down the right gave Gerrard the chance to find Torres eight yards out, only for the Spaniard to again fluff his attempted shot into the air which Benayoun headed weakly at a grateful van der Sar.

It was the latest disappointment in a season of many for Liverpool.