Three costly error-strewn moments in the opening 20 minutes proved defining in a lively game at Brisbane Road where League One promotion favourites Birmingham emerged with a 2-1 win against Leyton Orient.

Keshi Anderson and Alfie May scored for the visitors either side of a goal by Ethan Galbraith.

Orient goalkeeper Zach Hemming’s howler in the seventh minute gifted City the lead when his intended pass to a team-mate was intercepted and Anderson steered the ball into an empty net.

But in the 14th minute, Birmingham keeper Bailey Peacock-Farrell was also left red-faced when he gave the ball away and Galbraith drilled it low into the corner of the net.

May then restored the visitors’ advantage after 20 minutes when the ball was deflected into his path off an O’s defender before he netted from six yards.

The teams went toe-to-toe after the break, with Dan Agyei coming closest for the hosts while Paik Seung-Ho saw a curling shot from 20 yards narrowly miss the target.