For me it was the 2016/17 UCL top scorer battle. After the round of 16 ended, Messi was the favourite to finish the season as the top scorer, with 11 goals in only 7 games played. At the same time Cavani had scored 8, Lewandowski and Aubameyang had scored 7. Meanwhile Ronaldo had scored only 2 goals until the quarter-finals started, even his teammate Morata had scored 3 and he only started one game in the competition.
Flash-forward to the end of the campaign and Ronaldo finished the season with 12 UCL goals, after his brace in the final to help Real Madrid in their 12th (then) UCL trophy. A truly iconic turn-around that isn’t talked about much in my opinion. Any other suggestions?
Obviously biased as a Sunderland fan, but Gus Poyet keeping us up in 2014. We were bottom of the table on Christmas day and went on to finish 14th, with that run of games in April to May; an away draw to the eventual champions, beating Man Utd at Old Trafford, and ending Mourinho’s 77 game unbeaten home record as Chelsea manager.
7 points adrift with 6 games to play, including Man City, Chelsea and Man United. It’s certainly the greatest relegation comeback of the Premier League era.