Adrian Clarke looks at key tactical points in Matchweek 1.
The 22-year-old moved to The Hawthorns on a permanent deal in the summer after playing a key role in their promotion to the Premier League.
Slaven Bilic is building a creative side in which the talented Diangana will play an integral part.
His pre-season form was excellent prior to departing West Ham United and Baggies fans will hope he can continue this on Sunday.
Diangana's quality on the ball and ability to create an opening out of nowhere can be the difference in a tight match.
From turnovers or when West Brom are enjoying possession, he likes to drive forward and run at defences.
No Championship player completed more dribbles in 2019/20 than the 3.52 per 90 minutes made by Diangana.
Three of Leicester's back four from last season will not feature when the Foxes kick-off their campaign.
With this in mind, I would expect Bilic to approach the match with a positive mindset.
In a 4-2-3-1 formation, he will encourage his team to be adventurous and target the flanks, using the speed and trickery of their wide players.
Diangana laid on six assists in 23 starts last season and his inventive play made him dangerous in the final third.
As well as his creativity, the England Under-21 international also offers West Brom a goal threat.
Using his pace to sprint in behind defenders, he scored eight times at a rate of one every 233 minutes.
If Brendan Rodgers' backline allow themselves to be caught square or on their heels, Diangana has all the attributes needed to take full advantage.
Expect the winger to showcase his ability and play a key role in West Brom's attack this term.
Part 1: Leading from front will be key when champions collide
Part 2: Brighton's new-look defence set for Werner test
Part 3: Deputy wing-backs must step up for Wolves
Part 4: Ward-Prowse can set tempo for Southampton
Part 6: Reed provides balance to Fulham midfield
Part 7: Allan can steady Everton midfield ahead of Alli battle