After a goalless first half, Leicester took the lead in the 54th minute with a free-kick from James Maddison but super-sub Adams scored in the 68th and 84th minute to seal Southampton’s first win of the new season and also the first since April.

“What the manager has instilled in us is to never give up and keep believing. We did that today,” Adams said.

“First half was tough, in tough conditions, but we stuck in there and got the points.”

Adams scored nine minutes after coming off the bench, finding the target with a low strike following a long throw-in, while the hosts were left to rue their poor defending.

The Leicester-born Scotland forward then completed his double with an acrobatic effort as he volleyed home a cross from James Ward-Prowse, prompting boos around the King Power Stadium.

Adams almost bagged a hat-trick in stoppage time, but his shot rebounded off the post. The miss, though, did not matter as Ralph Hasenhuettl’s side picked up three points against the 2016 league champions and moved up to 12th in the standings.

“You could see at the start we had some respect for playing here better than we can. After the goal, we see we have nothing to lose and the guys step up. We played some fantastic football,” Hasenhuettl said.

Earlier, Maddison had put Leicester ahead after he whipped the ball around the Southampton wall from a freekick and found the bottom corner of the net, marking his second goal in three games.

Leicester dominated possession but had only one shot on target out of their six attempts.

The East Midlands club slipped to 18th and are yet to register a win this season after losing two matches and drawing the other.