Celtic stunned the log leaders with a 3-1 win at Lucas Moripe Stadium last night.
The result prevented Sundowns from matching Kaizer Chiefs' record of going 19 consecutive league games without defeat in a single PSL season.
"Any coach will feel great to beat a team that is on top of the table and it is no different with me," says Letsoaka, who also got the better of Downs when in charge of Golden Arrows earlier in the campaign.
"Beating Sundowns, a team as organised as Sundowns, going about 18 games unbeaten, I must say I am excited.
"I am also excited for the players that wanted it so much."
Letsoaka, however, remains wary of the threat of relegation. Phunya Sele Sele are 12th on the Absa Premiership table with 25 points from 23 games - eight points above the drop zone, and six points behind eighth-placed Free State Stars.
"We must try to get away from relegation and try to get points as much as possible from the teams that are below us. That's what we are trying to do.
