O'Shea was named by Slaven Bilic at centre-back for the tie with their Championship rivals at the Hawthorns having been an unused substitute in both of their opening two league games this season, including for the draw with the Lions at the weekend.
It was a disappointing night for the Baggies as Millwall came from behind to win 2-1. But O'Shea certainly did not disgrace himself with his first appearance for the senior side.
The 20-year-old - who spent last season on loan at Exeter City - showed little hesitation when it came to getting stuck into challenges, while he also made a number of clearances for Bilic's men.
It was the kind of display that will leave the West Brom boss feeling confident that O'Shea will be able to step up if he is called upon during the coming months. The Baggies do not have a lot of centre-back options, so there is every chance that O'Shea will get the opportunity to build on his debut in the very near future.
And after he took to social media to comment on making his bow for the club this week, former Baggies boss Shan replied with an emotional message as he congratulated the youngster on making the most of his chance.
Here is Shan's message to O'Shea...
Congratulations on your debut Dara, you should be very proud of yourself young man.— Jimmy Shan (@Jimmy_shan78) August 14, 2019
Have something to tell us about this article?