When the goals were flying in at a record rate for Derby County at Bristol City last month, the normally poker-faced John Eustace couldn't contain his smile.
The pearly whites on display pitchside at Ashton Gate during the 5-0 win betrayed the "emotion-free" public persona the 46-year-old has curated in a year during which he has transformed the Rams from relegation battlers to promotion contenders.
"It was a fantastic win. We've gone to a top team and won so I'm not going to be grumpy about that," Eustace told BBC Sport about the shot of emotion he afforded himself that late January night.
The most obvious time Eustace allowed himself a euphoric outburst before that was on the pitch at Pride Park on the final day last season after a goalless draw with Stoke City ensured Championship survival.
It was a crucial point with club-defining purpose as the Rams avoided an immediate return to League One.
Victory against Bristol City - what was the club's biggest ever Championship win on the road - and the grin that accompanied it gave the clearest indication of what Eustace is trying to achieve at Derby.
Pragmatic football, finding substance in results rather than style in approach, has largely defined the 12 months Eustace has been in charge.
While Derby have scored in 21 successive matches - the longest ongoing streak of any side currently in England's top-four tiers - they have won just three of their 12 league games this season by more than a solitary goal.
But the former Derby midfielder - who in 2014, as a player under then England boss Steve McClaren, helped get the Rams to within a Wembley win of Premier League promotion - is not shy about admitting he wants more.
This from a head coach whose managerial career started more than a decade ago at Kidderminster, where one rival coach said Eustace had the Harriers playing like "non-league Barcelona".
With that in mind, was the five-goal dismantling of Bristol City that briefly had Derby in the play-off places a telling glimpse of what Eustace wants from his side?
"I just want to win," Eustace started in his typical matter-of-fact way.
But grinning, he quickly added: "You want to win with style and you want to win with passion, of course you do.
"And there's a certain way I want to play.
"When we lost in the play-offs [in 2014] and the season after, I thought we were a top-performing team. We could mix it up, we could play football, we were exciting on the transitions, we could build, we could be a possession-based team as well. We had great wingers, who were exciting, so that's something that I'd like this team to eventually be like.
"But if you don't win, you don't get that time to do it. So it's important that we just find a way to keep progressing at the football club."
It is not lost on Eustace that his year in the job makes him the 10th longest-serving boss in the division - with 14 clubs in the Championship having fired and hired within that time, racking up a total of 21 permanent managerial changes.
- Listen to BBC Radio Derby's interview as Eustace reflects on a year as Rams boss
- Why Szmodics deal signals Derby's Premier League intent
- Fit-again Morris could return against Swansea
When Eustace took the Derby job a year ago to the day, he readily admitted he was taking a "huge risk".
He had parachuted down 16 places when he decided to leave then promotion hopefuls Blackburn Rovers for a Rams side languishing near the foot of the table.
A 4-0 defeat at Queens Park Ranger a day after taking charge of Derby dropped them into the relegation places. Another two defeats after that had them bottom of the table with two months of the campaign left.
But Eustace oversaw an astonishing six wins and three draws in their final 11 games to keep them up.
Throughout the relegation battle, Eustace said survival was the aim but the club's long-term Premier League aspirations was what brought him to the club.
What came across as lofty ambitions for a side that have not played in the Premier League since 2008 and had been in administration just years earlier - when they were a week from going out of business - has become a genuine goal this season.
The high-profile capture of Republic of Ireland forward Sam Szmodics on loan from Ipswich Town on transfer deadline day was offered up by Rams chief executive Stephen Pearce as proof of Derby's desire to reach the top flight.
Szmodics was the 17th player the East Midlands club had signed across the two transfer windows this season.
With 19 players going over at the same period, Derby have been transformed almost completely since Eustace's arrival
"We want to play a certain way but we've got to have the personnel and quality to do it. And if we can't do that, we have to adapt," he said.
"We've certainly done that up to now.
"I want to play exciting, expansive football and given time I'm sure we can. We're making strides forward. But you can't just go from one extreme to the other - it has to be built over a period of time."
If Derby beat Swansea on Saturday, they could end the weekend in the play-off places.
Already Eustace says his side is "ahead of schedule" in their efforts to challenge for promotion.
And while the expectations placed on the side by the Rams faithful have shifted as a result, Eustace insists he won't get caught up in the hype.
"I'm never going to change, unfortunately," he said.
"The most important people for me are the group of players and if they see me getting carried away then they're going to get carried away. They have to stay level-headed.
"My job as a head coach is to stay virtually emotion-free and make sure that the players are very focused and know their jobs inside out."