Fred Onyedinma came off the bench to score his first league goal of the season to give Millwall their third consecutive away win and extend their unbeaten Championship run to six games.

Here are five things we learned... 

Millwall not at their best but still get the job done  

The Lions made just 34 successful passes in a lacklustre first-half display and despite chances for George Saville and Jed Wallace Neil Harris’ side were far from their best. Millwall were wasteful in possession and only improved once Onyedinma came on. The 21-year-old gave the visitors some much needed flair in the final-third and completed a fine 20-minute cameo by volleying home his second goal of the season.

Three away wins on the spin

It had been 13 away league games without a win before the Wallace struck an injury-time winner against Leeds in January, and that victory seems to have given Millwall the belief to go on and get more victories. That win at Elland Road was followed up by a convincing 2-0 win over Reading two-weeks later thanks to second-half goals from Lee Gregory and an own-goal. The Lions' third straight away win came courtesy of Onyedinma’s strike 13 minutes from time against at St Andrew’s.

Onyedinma breaks his goal drought in the league  

It had been 39 games since Onyedinma had scored a league goal with his last coming in a 1-0 victory over Southend at The Den on 11 February 2017. It was also his ever Championship goal at the 31st time over asking, after failing to score in his six appearances between 2013-2015 and any of his 24 league outings so far this season.

 Millwall’s first ever league double over Birmingham  

The Lions have played the Blues in 20 different seasons and this is the first time that they have beaten them twice in the same campaign. It was also just Millwall’s fourth ever win at St Andrew’s and their second on the bounce after the 1-0 win in February 2015 thanks to a second-half Alan Dunne goal.

Another impressive away following  

1,121 Millwall fans made the 235-mile round trip up the M1 and the three points would have ensured the journey home was a cheerful one.

It was the twelve time this season that Harris’ side have been backed by more than a thousand supporters on the road, which is impressive as the Lions average the third lowest home attendance in the Championship.