Marinos went into the match having posted a defeat and a draw in their last two outings, but did not look short of confidence as they raced into a fourth-minute lead.
Former Celtic star Shunsuke Nakamura grabbed the early goal - his ninth of the season - to give his side a lead they refused to relinquish for the remainder of the match.
Reigning champions Sanfrecce Hiroshima remain Yokohama's closest challengers after they too managed to get back to winning ways on Saturday.
Goals from Hwang Seok-Ho and Hisato Sato secured a 2-0 home victory against Albirex Niigata, ending a run of five matches without a win and reclaiming second place from Urawa Reds in the process.
Sanfrecce have Ventforet Kofu to thank for their ascent up the table, after Hiroshi Jofuku's men picked up a credible away draw against Urawa.
Ventforet initially fell behind to Yuki Abe’s 51st minute penalty, but claimed a point as Naoki Aoyama plundered an equaliser in stoppage-time to move his side six points clear of the relegation spots.
Elsewhere in J.League, Kashima Antlers kept up the pressure on the top three with a win at Jubilo Iwata, despite almost squandering the points late on.
Shoma Doi, Davi and Takahide Umebachi gave the visitors a 3-0 lead going into the final 15 minutes before Sung-Dong Baek and Yoshiro Abe struck what ultimately proved to be consolation goals.
Below Kashima, Tokyo moved above Cerezo Osaka and into fifth with a victory away from home against Nagoya Grampus.
Aria Hasegawa and Nemanja Vucicevic got the goals in a 2-0 win that ensured the hosts would drop down to 10th place.
Meanwhile, rock-bottom Oita Trinita lost their 18th match of season against fellow strugglers Shonan Bellmare, as a Kosuke Taketomi brace kept the latter's hopes of avoiding the drop alive with a 2-1 victory.
In other matches, Sagan Tosu picked up a 1-0 victory at Kawasaki Frontale and Vegalta Sendai also triumphed on the road as they beat Omiya Ardija 2-0.
In Sunday's only clash, Yoichiro Kakitani scored a late goal to extend Cerezo Osaka's unbeaten league run to seven matches in a 1-1 draw against Kashiwa Reysol, who took the lead through Masato Kudo.
