His first competitive game in charge of his new side ended in disappointment, however, as Horgan and co were beaten 22-19 by fellow 2010 Play-Off semi-finalists Glasgow Warriors at Firhill.
Leinster will be looking to bounce back immediately when they take on Amlin Challenge Cup holders Cardiff Blues in the Irish capital this Saturday, but Horgan has suggested that patience will be the key for Leinster supporters this season.
"We are still in the very early days of Joe putting forward his game plan," Horgan told the Irish Herald.
"He is releasing information to us in piecemeal fashion because it takes time to get the details right.
"We will evolve over the course of the season. It will take a certain amount of game time. We have under-performed so far and that has been as a result of player performance, players not making the right decisions."
Horgan, who will start on the right wing against the Blues, is convinced that the Round 2 encounter will be an exciting one for players and fans alike.
The recent emphasis on law directives encouraging quick ball has been met with applause by the Ireland and Lions international as Leinster look to rediscover an attacking flair that was sometimes hidden last season.
And with the Blues having started with a bonus-point win over Edinburgh on the opening weekend of action, Horgan is expecting an enthralling match up at the RDS.
"The Blues tried to play the ball off the ground as much as possible. They offloaded whenever possible. When they really got to grips with it, they deprived Edinburgh of the ball," added Horgan.
"I would suggest that is what they will try to do when they come to The RDS on Saturday and we will be trying to do something similar ourselves.
"If players try to slow up the ball with hands in or lying on, they are going to be blown off the pitch. That is coming through strongly from the IRB.
"On the other hand, the ruck ball is fast, which is always to the advantage of the attack. It is almost like a new game this year.
"The changes will make for a more spectacular game, a lot of phases, a lot of attacking rugby."
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