Leicester boss Brendan Rodgers told BBC Sport: "It's a very good win against a good team. We were too passive at the start, we took social distancing to the letter and didn't get close to them. After that we had some sustained attacks and ended up getting a brilliant goal.
"At half-time we had to reiterate the importance of fighting, you have to fight for every result and Southampton keep going. We were outstanding second half and should have scored more goals. We did the dirty work much better and Harvey Barnes showed again that he is a finisher now."
On Maddison's celebration: "I said to them there is lots of negativity around it but see it as a positive and be creative. Supporters still want to see players celebrate, the happiness, so be creative with it."
Southampton boss Ralph Hasenhuttl said: "It's never nice to lose a game but we had chances. We hit the bar, we fought with everything we have. We are definitely a team that is never giving up. The quality of the opponent was better than ours today.
"The first goal, you don't shoot at goal like that every day, it was fantastic from Maddison. We had good chances but we couldn't finish and that was the difference.
"It doesn't look good at the moment, we have a lot of injuries and not many alternatives. The good news is we have 29 points and they don't take them away from us. We did our best with the options we have. We have nine injured but we are fighting for everything."