The Reds dominated the early exchanges and took a 10th-minute lead through Maxi Rodriguez's deflected volley.
Craig Gordon saved well from Daniel Agger and Maxi Rodriguez to maintain some respectability for Sunderland.
Maxi Rodriguez hit the bar in the first-half, while Ngog missed three chances after replacing Torres.
Atletico Madrid's winger Maxi Rodriguez and Greece international full-back Vasil Torosidis have also been linked with moves to Liverpool.
Striker Andy Carroll scored an injury-time winner for Kenny Dalglish's men, who had led 2-0 through a Maxi Rodriguez double.
In a dour first half, Maxi Rodriguez hit the bar for the Reds, while Roger Johnson headed over at the other end.
That initial spurt of pressure saw Liverpool win a corner with Maxi Rodriguez heading the ball to Torres, but the Spanish striker's volley struck the post.
"You have Maxi Rodriguez, David Ngog, Ryan Babel, Joe Cole - they are quality players and it is a very strong squad and they look organised, " he said.
Ferguson and Benitez made a single change each to their teams, with Park replacing Dimitar Berbatov for United and Maxi Rodriguez coming in for Ryan Babel in the Liverpool line-up.
But, there were no signs that Liverpool were feeling the effects of their exertions in the week as they started brightly with chances falling to David Ngog, Maxi Rodriguez and Aquilani.
The Madrid side were trying to use playmakers Jose Antonio Reyes and Maxi Rodriguez to open up Bolton but, more often than not, the brave Andy O'Brien and Gary Cahill were quick to block the supply.
Diego Maradona's men doubled their lead when Messi and Maxi Rodriguez combined for Higuain to head home before Lee Chung-Yong halved the deficit by capitalising on a Martin Demichelis error with a superb finish beyond Sergio Romero.
This time, Messi and Maxi Rodriguez were allowed all the time and space they wanted to take a quick free-kick down the left and when Maxi's cross was flicked on by Nicolas Burdisso, Higuain had the simple task of nodding in.
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