The Blues boss insists Ramires' last-gasp spot-kick award was justified and is adamant his side was worth a draw against a disciplined and spirited Baggies side
Marriner pointed to the spot in the 95th minute after Ramires went down following a collision with Steven Reid in the penalty area, despite replays showing minimal contact between the two men.
The result saved the home side's blushes and extended Mourinho's personal unbeaten record in home Premier League matches to 66 games - and the Special One was adamant the outcome was fair.
"Yes [we deserved to draw]," he told reporters. "In the first half West Brom didn’t cross the midfield line.
"We didn’t create a lot because they defended very very well but we were the only team that tried to score and tried to win in first half, so when the attitude to the game is this one there is always one team deserves more to win than another.
"In the second half we had more space with the 1-0, we had a couple of good situations. They scored a goal which is a funny one, and the second one is a big mistake by the referee [for the challenge by Sessegnon on Ivanovic]. The fourth official told me 'You’re right', but it is a big mistake.
"After that our reaction was fantastic. It was a reaction which could have ended the game 3-1 [to West Brom], but we created lots of chances and missed a chance with an open goal.
"We threw everything at them and the penalty comes at a moment which is difficult for the team that’s winning to accept. But a penalty is a penalty, minute one or minute 94, and this one was a penalty."
Mourinho also revealed his decision to start Cesar Azpilicueta over Ashley Cole at left back was based on form rather than fitness, and hinted the Spaniard may continue in his new role.
"Because Azpilicueta is playing very well," he replied when asked why Cole was consigned to the bench. "He was [first choice] today. Let’s see what happens next week, but he played very well against Schalke and again in this game. He made zero mistakes.
"Of course when I’m losing and I have to play with three defenders, I prefer leave the three powerful guys in the air who can be a threat in attack and I sacrifice Azpi but he played two very good games."
When questioned over whether he harbored concerns over Cole's form, Mourinho replied: "No. I didn’t like his performance against Newcastle, I made the change against Schalke and the answer from Azpi was a good answer. I didn’t feel I had any reason to leave him out today."