The Norwegian, who last claimed 7.5 km sprint gold on home snow in Oslo in 2016, was the best on course on Saturday (13 February) to win her 11th career World Championships medal in 21 minutes 18.7 seconds.
France's Anais Chevalier-Bouchet was close, finishing 12 seconds off the pace after missing one of her shots in the standing position to finish on the podium at a World Championships for the first time since 2017.
Hanna Sola of Belarus, who also did not miss a shot in her two visits to the shooting range, won bronze, a further 2.4 seconds behind.
Less than a minute separated the top ten, with 10th-placed Hanna Öberg of Sweden 58.8 seconds behind Eckhoff.
Eckhoff has already tasted victory once in Slovenia, winning mixed relay gold on Wednesday.
The top 60 finishers from the race will take part in Sunday's pursuit, with athletes starting at the same time intervals in which they finished in the sprint.
Eckhhoff was very emotional in the finish area. After coming in 59th over the same distance at the world champs in Antholz last year she was pleased that she managed to show her critics that she still has what it takes to win major titles.
"I am so proud that I coped with the negative emotions," Eckhoff said.
"I have been told that I'm not good at Championships, and now I proved them wrong."
"I was ready to avenge last year and it was great to shoot 0-0 (with no penalties). It was very tough on the range. It was very emotional."