Jordan Rhodes came off the bench to net a 93rd-minute equaliser for Championship promotion chasers Middlesbrough at struggling MK Dons.
The Scotland international arrived from Blackburn Rovers in a reported £9million move at the end of the transfer window, and netted his first goal for his new club deep in added time.
Dean Bowditch had given the home side the lead inside the first 10 minutes, but Rhodes' looping header sent Boro back to the summit, a point clear of Hull City.
In League Two, third-placed Oxford United were held 2-2 at home by Mansfield Town, who are one position lower in the table.
A brace from Danny Hylton had Oxford in front after Matt Green had given Mansfield the lead, but the visitors rescued a point a minute from time thanks to Jack Thomas.
Elsewhere, Stevenage defeated Hartlepool United 2-1 and Wycombe Wanderers overcame Dagenham and Redbridge by the same scoreline in a game which saw both sides finish with 10 men.