
Second-placed Arsenal have 62 points from 31 games, 11 behind leaders Liverpool, who have a game in hand when they go to Fulham tomorrow.
Everton climb to 14th place with 35 points from their 31 matches, 15 points clear of the relegation zone.
Arsenal took the lead in the 34th minute with the first shot on target in the game as a poor header in midfield allowed Raheem Sterling to race clear and feed Trossard, who took a touch and drilled his shot low into the far right corner.
Everton were awarded a penalty two minutes into the second period when Myles Lewis-Skelly hauled down Jack Harrison in the box and Ndiaye netted his ninth goal of the season in all competitions to leave Arsenal’s flagging title hopes in tatters.