Nabil Bentaleb scored a brace for Schalke 04 as Manchester City erased a goal deficit to seal a 3-2 win in the first leg of their Champions League last-16 game.
The Royal Blues had a first half lead but succumbed to Pep Guardiola's men who ended the encounter at the Veltins-Arena with 10 men.
Aguero opened the scoring in the 18th courtesy of David Silva's assist but Bentaleb inspired the hosts' fight-back with two goals from the spot before the interval.
After the Video Assistant Referee adjudged Nicolas Otamendi to have touched a goal-bound shot with his hand, the 24-year-old stepped forward and converted his effort to draw both sides levelled in the 38th minute.