George Moncur scored the winner as League Two leaders Leyton Orient beat AFC Wimbledon 1-0 at Brisbane Road.
Moncur struck in the 64th minute when he drilled a shot from the left side of the area across a crowded box and into the bottom right corner.
The London derby often proved a feisty affair and both sides created chances to break the deadlock before Moncur’s telling blow.
The former Hull man was only denied a third-minute goal when Nik Tzanev produced a fine save and the Dons goalkeeper was again called upon to prevent Kieran Sadlier scoring on his home debut.
At the opposite end Ethan Chislett spurned a good opportunity when he sent a shot wide of the target before Orient keeper Lawrence Vigouroux denied Ali Al-Hamadi before the break.
After the interval Orient showed more cohesion, although Chislett was again thwarted by Vigouroux.
But Moncur then pounced to put the hosts in front as they opened up a four-point lead at the top of the table.