The Galway side extended their unbeaten run at home in the league this year to six matches as they overturned an early 13-point deficit to claim a 24-16 win against Munster on New Year's Day.
Having lost all six of their inter-provincial derbies last season, Connacht have now recorded triumphs over both Leinster and Munster this campaign to keep pace with their fellow Irish sides in the GUINNESS PRO12 table.
And with the likes of centre Robbie Henshaw putting in a momentous performance in midfield, Lam is confident his side are well placed to sustain their challenge to the league's leading teams.
"I think Leinster was big in round three but it was round three," said Lam.
"Where the table sits now and what is riding on the game, the fact that we are starting the mid-season and we needed the four points, that was first and foremost.
"But I am extremely proud of the guys, it was a game that we had to win.
"I said at the start of the week that we pick a game plan around the battle that we will face, and, watching what Munster did to Leinster last week, we put a bit of work into it this week.
"Fair play to the boys, they did it together and it was a fantastic effort.
"In all of my time in Galway I have been hearing about the wind and hearing about the rain, you get a little bit and that was probably the worst we have had.
"[Henshaw] just gets better and better. It's only his second game with Bundee [Aki] but the two of them get on really well.
"This whole thing that we are doing is that we have a small squad, but in the group there is massive competition."
Click here to view the best images from Connacht's historic triumph over Munster
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