On a dramatic afternoon at Stamford Bridge, Chelsea equalised through a goal which contravened rules - Samuel Eto'o kicked a ball bounced by Cardiff goalkeeper David Marshall, leading to Eden Hazard's first goal - Mourinho was sent to the stands for berating the officials and the Blues finished with a flourish to move second in the table behind Arsenal.
Asked how close Chelsea, who play Schalke in Champions League Group E on Tuesday, are to their best, Holland said: "I think you see flashes of it.
"There aren't many teams at the moment who are hitting that maximum level consistently.
"It's an impossibility to be rolling along beautifully week after week after week.
"What you have got to accept is that when you're flowing, things flow, when you're not flowing you've still got to get results that give you a chance of being around for the titles.
"That's what we're doing at the moment that perhaps we haven't always managed to do previously."
Chelsea have relied on a late rally in their last two Premier League games, in the 3-1 win at Norwich and against Cardiff.
"It's a sign of progress," Holland said.
"The objective at Chelsea is always to win the league.
"At Christmas time for the last two seasons we've been out of the race.
"As long as we're within range and close when we get to the business end, the last few weeks, then I think we have a good chance.
"We have a manager who has been there before and seen it and done it and we have a group of players that I think are growing as the season goes on, becoming more consistent and are young enough to also improve as the season goes on."
Holland may find himself addressing the media more often as Mourinho faces a suspension for his dismissal for frustrations which were, his assistant believes, totally justified, particularly in relation to perceived time wasting by the visitors.
The breaking point for Mourinho was when, after Eto'o had put Chelsea in front for the first time, he sought a tactical change with the introduction of right-back Cesar Azpilicueta.
Mourinho had already introduced a forward for a full-back - Fernando Torres for Ryan Bertrand - to play with a three-man defence and was eager to adopt a more cautious approach once his side had taken the lead.
According to Holland, procedure was followed and fourth official Trevor Kettle informed Azpilicueta was to come on following the goal and Mourinho had dished out his instructions.
Yet, Kettle and referee Anthony Taylor did not make the substitution.
"For a few seconds, we didn't have a player in the position that we thought we should have a player, because of the confusion," Holland said.
"I still don't understand now why the fourth official didn't allow us to make the change."
Mourinho's potential to combust is well-known but his demeanour at Chelsea thus far has been of a content manager. The touchline dismissal, Holland says, was a demonstration of competitiveness.
Holland, who was promoted to work with the Chelsea first-team under Andre Villas-Boas in 2011, does not believe Mourinho is any more intense than the previous coaches.
But he praised the Portuguese's proactive approach, such as withdrawing a full-back and adding a forward in chasing a game.
Holland said: "That's something he's always done in his career and it's something we're gaining rewards from, certainly in our recent games."
One down side was the defensive lapse which allowed Cardiff's Jordon Mutch to give the visitors the lead.
Rather than point a finger at David Luiz, who left the ball, allowing Mutch to nip in and clip it over Petr Cech, Holland blamed a rare collective failure.
"I wouldn't say that David made a mistake," Holland said.
"It was a mistake from our defenders' and our goalkeeper's point of view in that the goalkeeper thought the defender was going to deal with it and the defender thought the goalkeeper was going to deal with it.
"It's not something that is characteristic. I can't remember the last time something like that happened."
Chelsea will make a late decision on whether Ashley Cole (ribs) and Andre Schurrle (leg) travel to Germany on Monday after the pair missed the Cardiff clash.
The Schalke game is their second of five in 15 days, with Manchester City visitors to Stamford Bridge next Sunday.
Source: PA
Source: PA