Monday night marked the start of the FIFA Ultimate Quaran-Team Cup and the Millers' journey to potential virtual glory began away to Colchester United, and it was Rotherham United who edged a seven-goal thriller.
Freddie Ladapo popped up with a brace to send the Millers on their way and Josh Koroma also found the back of the net, but it was Kyle Vassell's 69th-minute strike that proved to be the decisive one in an enthralling encounter.
Controlled by Rotherham United ESports player Ben Galloway, the Millers got off to a slow start and they were forced to weather a storm from the hosts. Despite showing signs of getting back into it, they could only withstand the pressure until the half-hour mark, with Luke Norris slotting one past Dan Iversen to put Colchester ahead.
That lead didn't last long, however, and conceding seemed to spark Rotherham into life. Vassell saw his initial effort saved by the virtual hands of Dean Gerken, but Ladapo was the quickest to react to the loose ball and he levelled things with 34 minutes on the clock.
Vassell was at the heart of things again in stoppage time as the Millers pulled themselves ahead in spectacular fashion. Koroma played a neat one-two with the Northern Ireland international before curling one into the top corner via the underside of the crossbar to send his side into the break with a 2-1 lead.
Following the restart, the Millers didn't waste time as they widened the margin to two goals. Vassell once again provided the assist with a neat pass into the feet of Ladapo, and he finished with great composure to double his own tally just four minutes into the second half.
Norris then pegged Rotherham back just a few minutes later as he scored his second of the game, but Vassell restored his team's two-goal cushion on 69 minutes as he latched onto a Ladapo pass to slot one beyond the reaches of Gerken.
With 10 minutes remaining, Kwame Poku lobbed one over iversen to bring the Essex-based outfit back within touching distance, but the Millers soaked up the late pressure to progress into the next stage of the competition.