Manchester United made it two wins from two games on Tour 22, as Erik ten Hag's side came from behind to defeat Melbourne Victory by four goals to one.
Harry Maguire then went close with a header, before McTominay made it third time lucky, following two previous efforts, as his deflected effort looped over Paul Izzo and into the back of the net.
Then, just moments before the break, the Reds went ahead. A clever passing move was delightfully finished by Anthony Martial, after Diogo Dalot's cross from the right found its way to the Frenchman. The ball was well-controlled by our no.9, who then calmly finished to notch his second goal of pre-season so far.
As the second half rolled around, Ten Hag opted to make 10 changes, with Donny van de Beek, Marcus Rashford and new summer signing Tyrell Malacia all introduced prior to the restart.
Zidane Iqbal showcased his talents with a superb piece of skill, as the Reds continued to dominate possession.
With 15 minutes to go, United had a third, as Eric Bailly burst forward to feed Rashford. The England international nudged his effort beyond Izzo, and opened his Tour 22 account in the process. Former Reds winger Nani was then introduced with just a few minutes to go, making his debut for the hosts seven years after his departure from Old Trafford.
The scoring was then completed with just minutes remaining, when Edmond Lupancu diverted a Tahith Chong cross into his own net to make it 4-1, ensuring a second pre-season win for our new Dutch boss.
MATCH HIGHLIGHTS
The short version of the match highlights are available on ManUtd.com and the United App (see below).
Extended editions, including the full 90 minutes, will be made available later on matchday.
MATCH DETAILS
United: Heaton, Dalot, Lindelof, Maguire (c), Shaw; McTominay, Fred; Sancho, Fernandes, Elanga; Martial
Subs not used: Bishop, Pellistri, Wan-Bissaka, Hannibal, Kovar, Garnacho.
Goals: McTominay 43, Martial 45+1, Rashford 78, Lupancu (OG) 90.
Victory: Izzo, Barnett, Broxham, Roderick, Timotheou, Nigro; Brillant, Marchan, Brimmer; Folami, Oikonomidis.
Goals: Oikonomidis 5.
Bookings: Roderick.
Subs not used: Acton, Prso, Wilson, Adams, Taleb.
NEXT FIXTURE
United's next test of Tour 22 comes in just four days' time, when we face fellow Premier League side Crystal Palace. That game will also take place at the Melbourne Cricket Ground, with Tuesday's (19 July) kick-off scheduled for 11:10 BST.
Patrick Vieira's side proved a tough test for United last season domestically, beating us 1-0 on the final day of the campaign. Fred's goal was the only difference when the two sides met at Old Trafford last December, and attention now turns to next week's pre-season showdown.
Every pre-season game - including our clash with Palace next week (11:10 BST) - will be shown live on MUTV, now available in our app and on ManUtd.com.