Pep Guardiola bemoaned Manchester City's failure to kill off Middlesbrough after the Teessiders grabbed a last-gasp equaliser at the Etihad Stadium.
Marten de Roon headed home in injury time as Boro snatched a 1-1 draw in a Premier League clash dominated by City for most of the previous 90 minutes.
Sergio Aguero had put City ahead with his 150th goal for the club just before the interval but the hosts failed to make the most of numerous other chances.
City registered 18 shots to Boro's none in the first half alone but their intensity dropped after the break and their midweek Champions League exertions against Barcelona may ultimately have caught up with them.