The centre-half stepped up in the 24th minute to surprise Simon Mignolet and fire the Premier league leaders in front.
It was the Brazil international's first Chelsea goal since his return to Stamford Bridge last summer.
But while his side-footed technique can work wonders, Luiz admitted it could have come at a cost.
He has been a consistent figure in Antonio Conte's defence this season, but a knee issue is plaguing him on and off the field.
Late in the first half he also went down clutching his knee and came back after the break with strapping.
David Luiz suffered with a knee problem during Chelsea's draw with Liverpool
My knee is hurting and I can't train every day
But he managed to see out the game as Liverpool pulled one back to draw 1-1, and Luiz was left with mixed emotions about the result.
"Sometimes you need to try the surprise," Luiz said on his free-kick.
"I'm not in the best position to take free-kicks because my knee is hurting and I can't train every day, but in a game you need to see the opportunity.
"I'm pleased I scored."
Chelsea player ratings against Liverpool
Tue, January 31, 2017
Express Sport brings you Chelsea's player ratings from their clash with Liverpool
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Thibaut Courtois – 6.5
On taking a point against Liverpool, he added: "It is never easy to play here at Anfield and win points.
"We had an opportunity to win the game, and we're unlucky we didn't win it. But it was a good result."
Following tonight's games, Chelsea sit nine points clear at the top to second-placed Tottenham after Arsenal lost 2-1 to Watford at the Emirates.
Meanwhile, Jurgen Klopp's Liverpool are fourth and still 10 points off the Blues.