Justin Tucker kicked a field goal as time expired to guide the Baltimore Ravens to a 29-26 victory over the San Diego Chargers in their AFC clash at M&T Bank Stadium.

The Ravens took the lead when Tucker capped a strong opening possession from his side by firing a 48-yard field goal through the posts.

San Diego rallied with a strong drive and levelled the scores after Philip Rivers's offense was stopped just short of the redzone, but Josh Lambo kicked a 42-yard effort.

Tucker put the Ravens back in front with a 29-yard effort, and the Chargers capitalised on the Ravens' struggles as they took the lead when Rivers fired to the endzone for Malcom Floyd, who managed to make the touchdown grab despite being held by a defender.

Baltimore hit back as they converted on fourth down to put themselves inside the 10-yard line of the Chargers, where Flacco fired to Crockett Gillmore in the flat for the go-ahead touchdown.

The game turned again just before the break as Rivers notched his second strike of the match when he sent the ball to the back of the endzone for Keenan Allen to make a leaping grab for the score, but the extra point was blocked, handing the visitors a three-point lead at the break.

Tucker notched his third kick of the game when he put an effort from 48 yards through the posts, but the Chargers extended their advantage as Rivers connected with Floyd for the second time in the match for a 70-yard touchdown.

The kicker's boot brought the Ravens within four points at the end of the third, and Flacco engineered his best drive of the match when he moved his team to the goalline before he crashed over for the score himself to put John Harbaugh's team ahead.

However, Baltimore were dealt a blow when Steve Smith was ruled out for the rest of the game with an Achilles injury, which may leave his season in doubt.

San Diego levelled with time running out as Lambo converted from 49 yards, but the Ravens secured the victory when the Chargers were penalised for pass interference, which moved the ball into Tucker's range and he made no mistake firing his strike through the posts.

The result leaves the Ravens at 2-6 in their season, while the Chargers lost their fourth match on the bounce to drop to 2-6 in the AFC West.