The hotshot from Kilkenny continued to prove his worth in front of goal in 2011-12.
As well as chipping in with goals for the U18 team, Drennan was on target five times in 13 appearances for the reserves.
Drennan finished 2011 strongly with a goal in the second string's 2-1 win over Swansea City and he started 2012 in the same vein by finding the target in a 1-1 draw against Arsenal.
It was a superb brace from Drennan in a 2-0 win at Sunderland that clinched Villa's fourth Barclays Premier Reserve League South crown in the space of five years.
He followed that up by netting yet again in the reserve team's final regular league season fixture at Fulham.
Drennan also featured four times in the NextGen Series, scoring at Villa Park in the 4-1 win over Norwegian side Rosenborg.
In the quarter-final stages of the prestigious European tournament, Drennan came close to firing Villa to glory against Marseille but his extra-time effort was harshly ruled out for offside.
The Republic of Ireland U19 international began his academy scholarship in 2010-11.
He immediately demonstrated his impressive goalscoring knack by bagging 10 goals in the Barclays Premier Academy League and once for the reserves.
That strike for the second string in the early-season win over Blackpool was particularly memorable - a delicate chip over the goalkeeper just moments after coming on as a substitute.
Drennan, who had huge potential as a hurling player before heading to England to pursue his Premier League dream, also made a big impression on the international stage.
He scored goals for Ireland U16s against Israel and Denmark at the end of 2009 before hitting a hat-trick against the Czech Republic.
The talented forward went on to receive Ireland's U16 player of the year award and was later called up to the U17 side for the European Championship Elite qualification group.
Drennan turned 17 in February 2011 and celebrated his birthday by singing his first professional contract with Villa.