Arsenal have now moved up to 13th in the table and sit nine points clear of the relegation zone.
But Saka, who provided the assist for Lacazette, was forced off in the last 10 minutes of normal time.
After initially going down in pain, the stretchers were prepared to bring him off but he was able to continue.
However, it was a brief renaissance and Saka – who was named man of the match – eventually limped off.
He didn’t have to go down the tunnel for treatment and was pictured smiling in the stands but he may still face a race to be fit for their next game against West Bromwich Albion on January 2.
And Arteta gave an update on his fitness after the contest.
Asked if the injury was serious, he replied: ‘Hopefully not.
‘He was limping but I think he took a strong challenge there but hopefully he will be fine.’
‘I think he’s having the right progression. I think he’s got the right people around him in his house in his entourage.
‘And then he’s got the right teammates as well to support him all the time, give him confidence, keep his feet on the floor, but as well to give him support and confidence.
‘And then hopefully we can be the right coaches around him, be the right club to see the player that he can be in the future.’
Lacazette was impressed with his young team-mate’s performance and told Amazon Prime after the match: ‘Every game he improves.
‘Even though he’s young, he shows his quality. Everyone is happy with him.’