Los Blancos took a lead in the first leg of the tie with an impressive 2-1 win in Amsterdam. Benzema opened the scoring after an hour, and while Hakim Ziyech equalised for the hosts, Marco Asensio was on hand to win it for Real Madrid with three minutes to go.
The France international was asked about the problem that forced him off, but he said "I'm fine, I'm going to rest for a day or two and that's all," per Santiago Siguero of Marca.
As relayed by Dermot Corrigan of ESPN FC, prior to the game Benzema had been dealing with a back issue:
Real Madrid have surged into form of late following a difficult start to the campaign. Not only are they now in a strong position to progress into the Champions League quarter-finals, they are in contention to make the Copa del Rey final and just six points behind La Liga leaders Barcelona.
While a number of Madrid players have seen their form dip significantly throughout the course of the campaign, the forward has been a consistent presence at the sharp end of the attack.
His goal at the Amsterdam Arena saw the Frenchman reach a landmark in European football's top-tier club competition:
The outing also saw Benzema reach 450 games for Real Madrid since joining the club from Lyon 10 years ago:
The No. 9 has suffered criticism in his career at the Santiago Bernabeu despite his goalscoring record. This season he's been among Los Blancos' best players.
While the team have suffered in attack following the sale of Cristiano Ronaldo to Juventus in the summer, Benzema has appeared to relish taking on more responsibility as the central striker.
On Wednesday he did exactly that, finishing after some excellent play from young winger Vinicius Jr. Broadcaster Mina Rzouki noted that the Brazilian and Benzema are building up a relationship in the final third:
Given his potency in front of goal and ability to link play, if the Frenchman was absent for a sustained period of time it would be a blow for manager Santiago Solari.
Benzema doesn't appear to be too concerned about the issue, though, and given he was suffering with a knock prior to this game, Solari will be pleased to have seen him get through the match in the Netherlands.
The contest was the third tough away game in a row for Los Blancos, as they've faced clashes with Barcelona and Atletico Madrid prior to the Champions League encounter. To have made it through those games with two wins and one draw is testament to a team making progress at a perfect time in the campaign.