A loss on Sunday pushed 2007-08 V-League champs Binh Duong out of first place while reigning champs Da Nang fell to fifth.
Binh Duong, who made their way to the semifinals of Asia's second-tier AFC Cup last year, suffered a 2-3 away defeat at Long An Stadium to the league's 2005-06 champions Dong Tam Long An (DTLA).
The hosts DTLA took the lead after Tanzanian midfielder Mrwanda Danny David's 28-minute opener but Brazilian-Vietnamese striker Huynh Kesley's and South African striker Philani's goals in the 34th and 70th minutes put visitors Binh Duong up front.
However, Congolese striker Tshamala Kahanga's double in the final minutes earned a win for DTLA.
Binh Duong slipped to second with 32 points while DTLA remained in 12th position out of the 14 teams in the league with 21 points.
Hanoi T&T climbed to the top from the second spot with 34 points after a 1-0 away victory at Thien Truong Stadium over Nam Dinh, who remained second to last with 11 points.
Defending champions Da Nang dropped one more place to fifth with 28 points after a 0-1 away loss at Pleiku Stadium to the league's 2003-04 champs Hoang Anh Gia Lai, who stayed in 11th spot with 22 points.
Ho Chi Minh City's representative Navibank Saigon suffered a 1-3 away defeat at Hang Day Stadium to Hoa Phat Hanoi, who jumped two places to seventh.
Navibank Saigon remained at the bottom with the same points as Nam Dinh, making both teams' relegation to the second-tier First Division nearly inevitable.
Hai Phong Cement jumped two spots to third with 29 points after a 1-0 home win at Lach Tray Stadium over Ninh Binh, who remained in sixth with 24 points.
The 1-1 draw at Cao Lanh Stadium pushed the hosts Dong Thap and the visitors Khanh Hoa one place down to fourth and eighth with 29 and 24 points respectively.
Nghe An, who became the first champions of the league in 2001, defeated Thanh Hoa 4-1 at Vinh Stadium.
Nghe An climbed one spot to ninth with 23 points while Thanh Hoa fell two places to 10th with one point less.