J.League wrap: Hiroshima top Sendai, standings
Having started the game in second position, Hiroshima claimed victory and top spot thanks to Yojiro Takahagi's 78th-minute goal, which handed Sendai their first defeat in five games.
Fans at Hiroshima's home stadium had to wait until after half-time on Saturday for the first goal as Kazuyuki Morisaki struck in the 48th minute to give the hosts the lead.
Sendai hit back in the 70th minute through Shingo Akamine but eight minutes later Takahagi clinched the three points for Hiroshima that saw them leapfrog the visitors in the standings.
Hiroshima are now on 47 points from 25 matches, two ahead of Sendai and Urawa Reds.
Urawa drew level with Sendai after a 2-1 comeback victory away to Yokohama F. Marinos.
Yokohama took an early lead through Brazilian striker Marquinhos in the fifth minute but the Reds were level at the break thanks to Yosuke Kashiwagi's 23rd-minute strike, while Yomoaki Makino scored the decisive goal in the 64th minute.
An injury time goal from Junya Tanaka ensured reigning champions Kashiwa Reysol snuffed out any chance of a comeback by bottom-club Consadole Sapporo in their 3-1 win.
Kashiwa led 2-0 at half-time thanks to goals from Hidekazu Otani and Masato Kudo but when Shota Sakaki scored in the 81st minute Sapporo still had hopes of snatching a point.
But Tanaka's goal in the fourth minute of second-half injury time ensured Kashiwa won their second match in a row and moved into sixth position.
Omiya Ardija moved out of the relegation spots with a shock 1-0 win over Sagan Tosu with Gamba Osaka slipping into the drop zone thanks to a 1-1 draw with fellow strugglers Albirex Niigata.
Shinzo Koroki's two goals for Kashima Antlers were not enough for victory as they let Kawasaki Frontale back into the game for a 2-2 draw, while Jubilo Iwata defeated Vissel Kobe 2-1.
In other results, Shimizu S-Pulse drew 1-1 with Tokyo and Nagoya Grampus knocked off Cerezo Osaka 2-0.