The 22-year-old winger was one of the standout performers in Arsenal's 2-1 win away to the Premier League basement dwellers, with the Hale End academy product bagging his third goal of the season in the league.
They are now fifth, a point from United, who are in fourth.
The Yorkshire side did at least score for the first time since Jan Siewert replaced David Wagner as head coach, however, thanks to Sead Kolasinac's late own goal.
However, Jurgen Klopp's men were back to their best as they swept Bournemouth aside, with Sadio Mane, Georginio Wijnaldum and Mohamed Salah all finding the back of the net in style.
Emery's side now have a two-week break from the Premier League as they take on BATE Borisov in the Europa League, but return to domestic action on February 24 when they host Southampton.More news: Life Sentence For Toronto Serial Killer Bruce McArthur
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Earlier in the day, Manchester United shot into the top-four after they trounced Fulham 3-0 at Craven Cottage. On Saturday The Gunners ran out 2-1 winners at Huddersfield as they ended an embarrassing winless streak of six matches away from the Emirates.
Arsenal manager Unai Emery has kept his faith in Iwobi despite the constant criticism who has started 15 games in the Premier League this season.
"I think this season we have conceded goals too easily", Leno added. We have to work on this because the defence for me is the most important thing to enable us to get back into the top four.
The battle for Champions League qualification looks set to go to the wire, with a single point splitting United in fourth and Arsenal in sixth, although Chelsea have a game in hand. Our motivation is very great and every player wants to struggle every match and be consistent over 38 matches. We tried everything, we gave everything to win the game right until the end. "Every player was working and helping each other and today I'm very proud with our work".