Emile Smith Rowe was bought on as substitute within half an hour at the Emirates but only lasted 47 minutes, with Mikel Arteta claiming the Arsenal star was always going to struggle having been out for so long.
The academy graduate has been plagued with injury this term, which has hampered his first-team ambitions, but he was afforded an opportunity when Leandro Trossard was forced off with a concern of his own after 22 minutes. Smith Rowe occupied a role on the left of the Arsenal attack with Gabriel Martinelli coming in centrally.
Arteta opted to hook Smith Rowe for Reiss Nelson, the eventual match-winner, on the 69th minute. The player didn't appear to have picked up a knock, but made his return to the pitch earlier than planned having spent several months out nursing a groin issue.
The Arsenal boss said of Smith Rowe: "We didn't plan to throw him in so early in the game. We knew it would be difficult for him to last for 70 minutes after he'd had five months out, but I think he had a good impact. In the end, I felt that we needed something else, especially on the left, as we were attracting more players onto that side so we made the decision to change."
Smith Rowe hasn't started a single game in all competitions this term, with all nine of his appearances coming off the bench. The Gunners have largely enjoyed a settled starting XI which had limited his minutes before his injury struck.
Nelson's introduction was vindicated as the forward hammered home the winner in the seventh minute of added time. He, like Smith Rowe, is another academy graduate in the first-team picture, but is very much on the periphery. Nonetheless, Arteta spoke glowingly about what Nelson can offer.
"I always saw the potential, the talent and the desire for him to do it but he is in a different level right now," the Spaniard said of Nelson. "Football-wise, it was my decision in the last two games not to put him in the squad because we had different options, but he is knocking on the door and training really well. It is a good lesson for me and that coaches that we need him."
Arsenal's win means they remain five points clear after it looked as if they could lose ground in the title race. The Gunners saw Manchester City beat Newcastle on Saturday lunchtime, which allowed them to close to within two points of the league leaders.
The north Londoners then found themselves 2-0 down to relegation-threatened Bournemouth, who scored a goal within 10 seconds. Strikes from Thomas Partey and Ben White levelled the contest before Nelson's late, late winner sent the Emirates into raptures and re-establish their lead at the top of the Premier League.
"Probably, it is the loudest and most emotional moment we have lived together. Obviously, the journey we've been on added to the moment we had today," said Arteta.
