Matt Smith bagged a brace as Millwall defeated Barnet 2-0 in a behind-closed-doors pre-season friendly at Calmont Road on Saturday afternoon.
The striker scored headers in the 15th and 40th minutes to hand Gary Rowett's side - wearing their brand new 2021/22 home kit - a success in sweltering temperatures.
Naming a starting XI including George Long and Connor Mahoney - who both played 90 minutes - as well as Daniel Ballard and Maikel Kieftenbeld, The Lions took the game to their Vanarama National League opponents and almost took the lead with five minutes on the clock, but Tyler Burey sent a curling effort wide after cutting inside.
A defence-splitting ball from Shaun Hutchinson then put Burey through on 10 minutes, but after the attacker was hacked down on the edge of the penalty area, Mahoney's free-kick went wide.
Smith nodded wide from a Mahlon Romeo cross as Millwall kept up the pressure, and they were rewarded with the opening goal on 15 minutes as Smith was able to nod home from close-range after Murray Wallace's cross to the back post found the frontman.
Shortly after the half-hour mark, Mahoney - who looked impressive throughout - cut inside and sent a fizzing effort towards the top corner, but the ball whistled past the post.
Two minutes later Mahoney almost turned provider, but after he found the onrushing Romeo, his shot went over the crossbar.
However, with five minutes to play until the break, Mahoney registered an assist and Smith scored his second goal, as the striker was well placed to score from the winger's pinpoint cross.
There was almost a third before the break, but after Smith glanced on Murray Wallace's cross and Ben Thompson forced a save from the Barnet goalkeeper, a goalmouth scrambled saw The Bees able to hack the ball to safety.
Seven changes were made at the break, including names such as George Saville and Benik Afobe being handed 45 minutes, and the first opportunity of an energy-sapping half came on 65 minutes, but the latter headed Danny McNamara's cross just wide.
Six minutes later, Jed Wallace was able to rob the Barnet defence of possession and set up Afobe, but the striker dallied on the ball and was blocked from getting a shot in on goal from close range.
The Lions' pre-season campaign continues with more behind-closed-doors friendlies next week, ahead of trips to Gillingham and Ipswich Town at the end of the month.
Millwall First-Half XI: Long; Romeo, Ballard, Hutchinson, Cooper, M. Wallace; Kieftenbeld, Thompson; Burey, Smith, Mahoney.
Millwall Second-Half XI: Long; McNamara, Evans, Pearce, Cooper (A. Mitchell), M. Wallace (Tiensia); Mitchell, Saville; J. Wallace (Burey), Afobe, Mahoney.
Scorer: Smith 15' 40'