Villa are 11/4 (3.75) second-favourites to win promotion this month, while Boro are 3/1 (4.0) to reach the play-off final then beat Fulham or Derby, who are also vying for a return to English football's top table.
Tony Pulis’ side are 5/4 (2.25) to take an aggregate lead to Villa Park on Tuesday, having won 12 of their 23 Championship encounters under his tutelage including seven of their last eight home encounters.
Villa, though, have been victorious in three of their last five visits to Teesside - including a 1-0 triumph in this season's December fixture - and are 23/10 (3.3) to take the spoils again.
Five of the last 10 Championship play-off semi-finals have ended in a draw, a result that can be backed at 21/10 (3.10) .
Aston Villa’s Neil Taylor has struggled with injury lately and in the absence of alternative left-backs, Alan Hutton looks set to continue deputising.
Middlesbrough target man Rudy Gestede is still out with an ankle injury, so the men competing to start up top are Patrick Bamford and Britt Assombalonga.
The latter’s timely return to form might see him get the nod as he averages a goal every 137 minutes of football since March, and is a tasty 8/5 (2.6) to bag anytime.
Another in-form striker is Villa’s Lewis Grabban, the Championship’s second top scorer with 20 goals, a return which includes four in his last three starts.
The former Bournemouth man is an appealing 12/5 (3.40) to score at any point.
Preview and predictions
While both teams have clinical goalscorers, chances could be at a premium, with two pragmatic managers overseeing a contest in which nerves are likely to limit the confidence of both sides.
For that reason, our best bet is the 5/1 (6.0) on a 1-1 draw, which has been the score in three of the last six Championship play-off semi-final first legs.
Odds correct at the time of writing. Please gamble responsibly.