The West Ham goalkeeper brought down Oscar in the 21st minute at Upton Park before Frank Lampard dispatched the resulting penalty against his former club to set Chelsea on their way to a comfortable victory.
Oscar himself doubled the advantage 11 minutes later before Lampard claimed his second of the game eight minutes from time to round off the scoring.
Jaaskelainen's foul on Oscar came following a mistake from West Ham right-back Guy Demel and although the Finn was the last man, referee Foy deemed it not be a goalscoring opportunity and opted not to show a card of any kind.
The Chelsea manager is happy to accept Foy's ruling.
"I spoke to Chris Foy and he told me it was not a red card," he said.
"He was 10 metres away and I was 50 metres away. The referee and linesmen were very good.
"I thought it was a possible red card, but if Chris Foy says no then okay, no."
Mourinho went on to praise the performance of his players, making special mention to the solidity of the display.
"The game was good for us, the team were very comfortable," he said.
"I think we deserved the victory, everybody in the stadium must think the same because we were very comfortable.
"From the first minute to the last was very solid, very stable, very comfortable and I like that because everyone was committed to the clean sheet against an opponent that is always difficult.
"Every set-piece is a threat and they are very physical and aggressive."
Lampard ended a run of 10 Premier League games without a goal with a brace that takes him to five goals in his last five appearances against his old club.
"(Lampard) has nothing to prove," said Mourinho.
"Not to you, to the fans, to me or himself. He has nothing to prove he just has to enjoy the last years of his career and play the maximum he can.
"I think I come to him in the right moment for him, I was his manager in the best period of his career probably and now I come back to enjoy with him the last period of his career."
