Real on top in nine-goal thriller
Further strikes from the Argentinian and the Brazilian in the second period, as well as three Valencia goals, scored by Roberto Soldado, Jonas Goncalves and Jordi Alba, finished a game that ensures the battle for the title continues for at least another two weeks.
Just three days after winning the Copa del Rey, it was a very different line-up for Madrid, who meet Barcelona again in the first leg of their UEFA Champions League semi-final at the Santiago Bernabeu on Wednesday.
The goalscorer from Wednesday night's cup triumph, Cristiano Ronaldo, was left on the bench as Jose Mourinho changed all but two of his cup line-up. Goalkeeper Iker Casillas, a hero against Barça, kept his place, as did Ricardo Carvalho, who will be suspended for the Champions League match against Pep Guardiola's side on Wednesday.
Sergio Canales, also in for a rare start in midfield, saw a shot blocked after eight minutes, before in-form striker Roberto Soldado mishit a volley at the other end. However, it was all Madrid in the remainder of the half and Benzema hit the woodwork with a thunderous effort just short of the 20-minute mark.
Less than three minutes later, the French international put Madrid in front following a quick counter-attack. Higuain escaped down the right and sent in a low cross, which Valencia keeper Vicente Guaita was unable to intercept, and Benzema took his time at the far post, controlled and smashed the ball into the empty net.
Pablo Hernandez came close to an equaliser when he fired just wide after 28 minutes, but Valencia handed a second to Madrid on the half-hour mark. Jeremy Mathieu and Guaita got into a terrible mix-up in the area and both ended up leaving the ball for Higuain to slot home a simple second.
Higuain then set up Kaka for a third following another quick counter-attack after 38 minutes and the roles were reversed three minutes later, when the Brazil forward put a fourth goal on a plate for the Argentina striker. It was all too easy for Madrid and Valencia just could not cope.
There were jeers around the ground at half-time, but normal service was resumed for Madrid seven minutes into the second half, when Kaka set up Higuain for another simple finish to complete his hat-trick.
Valencia had never conceded more than five goals in a league match here, but that changed after 61 minutes, when Kaka nutmegged Marius Stankevicius and beat Guaita with a lovely finish. The goal clearly meant a lot to the Brazilian, but many of Madrid's players barely celebrated, perhaps feeling for their disheartened rivals.
In between Madrid's fifth and sixth goals, Soldado popped up to bag a consolation from close range and score his eighth in four games. Higuain then missed a great chance to make it 7-1 when he tried to chip the ball over Guaita.
Brazilian forward Jonas Goncalves later pulled another goal back for the hosts when he drove a low shot inside Casillas' right-hand post from the edge of the box. And Jordi Alba, who had been on the field for barely 90 seconds, then made it 3-6 with six minutes left, when he beat Casillas from close range.
Jonas almost scored a fourth for Valencia moments later and the hosts finished the game on the up against a Madrid side, now including substitutes Ronaldo and Xabi Alonso, who provisionally closed the gap on leaders Barcelona to five points. Even if Barca beat Osasuna, Mourinho's men have ensured the league title will not be decided for at least another two weeks.