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?