Ben Thompson and Fred Onyedinma take chance to impress for Millwall.

MILLWALL 4

O’Brien 35, 56 Thompson 47 Onyedinma 61

BARNSLEY 1

Potts 11

By Richard Cawley at The Den

This FA Cup tie might not have quickened the pulse when it was drawn out of the hat, but it’s still a shame that only 5,319 were in attendance to see an excellent Millwall display.

All of the goals were scored by players who had come through the Lions’ youth system with Ben Thompson and Aiden O’Brien the stellar performers.

Last season’s run to the last eight of the competition gave the South Londoners the chance to flex their giant-killing muscles as they took down Bournemouth, Watford and Leicester City – who all paid the price for rotating out their first-choice stars.

So an all-Championship encounter in the third round this year was all a little bit dull.

But the match itself certainly wasn’t boring. Millwall boss Neil Harris made six changes to his starting line-up and they produced a confident performance that once again showed they are anything but a long-ball outfit.

The key is that the Lions look to play in their opponent’s half – where any mistakes are not so costly.

“It’s just like Wembley again,” chanted the small cluster of Barnsley fans – alluding to the League One play-off final in May 2016 – after Brad Potts rammed them into an early lead at The Den.

It proved to be brutally premature. The Tykes had won their last five fixtures against Millwall but they were emphatically defeated this time around, Joe Williams’ dismissal only quickening their demise.

By that stage they were already trailing and the Lions could have finished with an even greater margin of victory.

It is a sign of the improved squad strength that Harris has to choose from that a solid, committed performer like Thompson has struggled to get much of a look-in since their promotion to the Championship.

On Saturday he was terrier-rific. The midfielder might give away height and weight to some of his opponents but that does not faze him one bit. He dominated in the middle of the park. His game is built upon unflagging energy levels and snapping into tackles – typified by the way he ended one Adam Hammill run in the first half. But he also netted for only the third time for the Lions, and first since April 2016, to put Millwall ahead for the first time in the contest.

O’Brien’s wait for a goal has not been as long, but then his role in the side demands a higher conversion rate. It had been 18 matches since he last got his name on the scoresheet, so walking away with a brace is a nice confidence-booster.

His call for Onyedinma to leave Jed Wallace’s cross saw him clip the ball past Adam Davies to make it 1-1. His second of the afternoon was the pick of the goals, curling home first time from the edge of the box.

Onyedinma became more influential after a quiet opening. Both his and Wallace’s pace were proving troublesome to Barnsley, it was a slight change in approach as there was not the same kind of aggressive press from the front without Lee Gregory in the starting line-up.

The fourth was all about the awareness of Steve Morison. Jake Cooper stepped out of defence and his bobbling pass to the veteran striker was dinked first time into the path of Onyedinma, who got to the ball before the sliding Jason McCarthy and curled beyond Davies.

It was his first goal of the campaign and might just be the catalyst for more to come from the 21-year-old, who despite featuring 23 times this season had struggled to reach peak form.

Williams’ red card stunted Barnsley’s prospects of staying in the tie. His lunge on Wallace saw Millwall’s players surround the Tykes’ number four and referee Darren Bond was quickly on the scene to mete out punishment.

The Lions record at The Den is impressive. Since the start of last season it is 29 wins, 10 draws and nine defeats. Their first season in League One under Harris saw them win 16, draw four and lose 10.

Despite them now competing at a higher level they have continued to be a major force on home territory.

Their stadium was not intimidating on Saturday in terms of atmosphere – like it has been for the visits of Championship big-hitters – but the players were in no mood to let Barnsley continue their successful run of results against them.