Nicolas Pepe and Alexandre Lacazette also got on the scoresheet to cancel out Stuart Armstrong’s opener in the third minute, but it was Saka who stole the show.
The 19-year-old forward struck just before half-time to score his fourth goal in eight games, while he also became only the second English teenager to score for Arsenal in consecutive Premier League appearances since Ashley Cole in 2000.
Saka has been at the heart of Arsenal’s recent resurgence, helping them win five of their last six League games, but Bellerin is convinced the youngster will not get carried away.
“It is so good because Bukayo is someone that is still really young,” said Bellerin.
“He still wants to learn. Even though he is doing so well, he has got his feet on the ground.
“When we work down that right side, we have to communicate all the time and he is someone that listens, that wants to help the team 100 per cent.
“I think that’s the most important thing - when a player wants to learn and wants to listen to their team-mates, and wants to help their team-mates and the team, that’s the most important thing.
“He has got a lot of that and I am so happy for him for the way it is going.”
Arsenal’s victory over Southampton came just three days after they had lost to Saints in the FA Cup fourth round.
Southampton had won that game 1-0 courtesy of a Gabriel Magalhaes own-goal and it brought an end to the Gunners’ defence of the trophy.
Defender Rob Holding, who made his 100th appearance for Arsenal last night, confessed afterwards that Saturday’s defeat motivated the side and they were determined to bounce back.
“After the weekend we knew we wanted to get them back because they celebrated and we were disappointed to go out of the FA Cup. It was a good bit of revenge,” he said.
“We were angry about the weekend’s result and we wanted to get back at them, so everyone was fired up for it.
“We came out the blocks straight away and Laca was unlucky in the first minute when straight through on goal.
“But he got his goal towards the end which made him happy, and his effort and work rate was top today, so he deserved the goal.”
Arsenal achieved the victory last night without their captain, Pierre-Emerick Aubameyang who was absent for the second game in a row due to “personal family reasons”.
And Bellerin said: “We are always behind our captain. We want the best for him.
“This win is for him. We had already sent him a message and we said: ‘We are going to win this game for you’.
“I am happy that we did and the support in the dressing room is amazing right now. We will support him always.”
The only negative for Arsenal last night was that they were without Kieran Tierney due to a calf issue, and Emile Smith Rowe and Thomas Partey both limped off during the second-half.
Arsenal play Manchester United on Saturday and Arteta is unsure if Tierney will be fit in time, while Partey and Smith Rowe will now also need to be assessed.
“[Smith Rowe] was injured for the game in the FA Cup so he wasn’t available,” said Arteta.
“We knew that he probably could not play the whole game today. He has some muscular discomfort so he had to come off again.
“Thomas was feeling some discomfort and hopefully it’s nothing, but he was struggling.”