Jonas Goncalves got an early opener before Soldado's solo show gave Valencia a 4-0 lead before the interval. Pablo Hernandez, Aritz Aduriz and Tino Costa added three more to round off the thrashing. The win means Valencia go second in Group E, a point behind leaders Bayer Leverkusen who beat Chelsea 2-1 on Wednesday.
Valencia now travel to London level on points with Chelsea and need at least a 1-1 draw to qualify, thanks to a better goal difference than the Londoners gained in the main from this result.
The in-form Soldado now has five goals in five Champions League games and with his eight goals in the Spanish league this season he is a strong candidate to add to two substitute appearances for the full Spanish side in the near future.
The Belgians arrived in Spain with slight possibilities of qualification and a decent reputation after a hard fought 0-0 draw in the first game of the group in September. Valencia knew that only victory would be enough and coach Unai Emery decided to leave left-back Jordi Alba, who recently made his Spanish debut, on the bench preferring to start Frenchmen Jeremy Mathieu in his place.
Valencia coach Unai Emery made it clear that goals were on his mind from the start. "We made sure we started at a quick pace looking for an early goal so we could look for a big result," Emery said. "We can go to London now in a confident frame of mind after this performance."
Both teams started brightly, mounting dangerous attacks into enemy territory to win early corners. And it was from one of those corners, taken short, that Tino Costa won enough space on the left to whip in a cross that was solidly headed home by Goncalves to ease the home team's nerves on 10 minutes.
Soldado then latched onto a Goncalves pass three minutes later and checked back from left to right foot to beat defender Khaleem Hyland and clip the ball past the advancing Genk goalkeeper Laszlo Koteles. Koteles had to be alert on 20 minutes to beat out a Costa free-kick and four minutes later he had to be at full stretch to tip away a shot from the Brazilian Goncalves, who pulled the strings for Valencia all night long.
At this stage Los Che were in total control, but the Belgian side did show signs of pegging back the lead with Fabien Camus and Kevin De Bruyne always quick to launch a counter-attack.
However two further goals on 35 and 39 minutes from the lethal Soldado finished any hopes the Belgians had. Firstly Soldado latched onto a defence-splitting pass from Goncalves and clinically finished, before stabbing the ball home from close range after Hernandez fired in a low cross from the right.
With the game decided, the second-half gave both teams the chance to introduce players, among those rested early was hat-trick hero Soldado. While Valencia continued to pass quickly and attack in numbers, the urgency of the first-half was not as prominent.
Hernandez and Pablo Piatti had drawn good saves from Koteles before the former curled a right foot shot home on 67 minutes. Substitute Aduriz then danced through a hesitant Genk defence two minutes later to add the sixth and Costa got his reward firing home with eight minutes remaining to round-off a disppointing evening for the Belgians.