The trademark smile is never far away from Daniel Ricciardo.

But the tears glistening in his eyes betrayed the truth that the affable Australian's Formula 1 career may well be over after 257 races.

Following his 18th place finish in Singapore — the last runner of all the finishers — Ricciardo spent a long time in the car before stepping out and conducting a visibly emotional interview with F1.com.

"A lot of emotions, because – look I'm aware it could be it," Ricciardo said, glistening with sweat after a gruelling race in the tropical heat.

"And I think it's also just [being] exhausted after the race, so it's like a flood of many emotions and feelings and exhaustion.

"The cockpit is something I got very used to for many years," he added, appearing to choke back tears and pausing repeatedly to compose himself.

"I just wanted to savour the moment."

Following the race and his media commitments, Ricciardo was given a small guard of honour by his RB team, with whom he shared some fist bumps and hugs, further suggesting that he would not return when the F1 circus visits Austin for the United States Grand Prix next month.

Ricciardo had composed himself by the time he spoke to UK's Sky Sports team, but acknowledged that the fairytale return simply hadn't come to fruition.

"I have to acknowledge it's obviously been a little bit of a race-by-race situation and I would obviously have loved the weekend to have gone better," Ricciardo told Sky Sports.

"It didn't, so I have to be prepared for this maybe being it.

Ricciardo returned to the Red Bull stable of cars following a disappointing stint away from the team, first with Renault and then McLaren.

After two disappointing years with McLaren — who are now fighting for the title with Lando Norris — he was let go and was without a drive for the 2023 season before Red Bull offered him a post as a reserve driver.

He was then promoted into a driving seat at Red Bull's sister team RB Racing midway through 2023 with a personal goal of returning to the primary team before his time was up.

However, the 35-year-old has been consistently out-performed by his 24-year-old teammate Yuki Tsunoda in both qualifying and in races, leading to questions over his ability to compete at the top of the sport.

"I always said I don't want to come back just to be on the grid, I want to try and fight back at the front and get back with Red Bull," Riccardo said.

"Obviously it didn't come to fruition so then I also have to ask myself the question: 'Well, then what else can I achieve and what else is there to really go for?'

"I put my best foot forward, let's say the fairytale ending didn't happen but I also have to look back on what it's been. Thirteen or so years and I'm proud."

Red Bull boss Christian Horner said that the team needed to make "difficult decisions" and "consider all of those options" during the four-week break between races, with New Zealander Liam Lawson tipped to step into the Australian's seat.

"These things are under constant review and there is obviously a much bigger picture other than just Daniel as we continue to look at all of our options as we move forward," Horner told Sky Sports.

"There's a natural break coming, with effectively almost a month's gap to the next race. It's only natural that you'll take stock and consider all of those options for the final part of the year.

"It's not to the detriment of Daniel. We know how he's performed. We've got a lot of data, a lot of knowledge of where Daniel is. It's a much bigger picture within the whole driver merry-go-round of what the future looks like."

Ricciardo has been one of the most popular drivers in the paddock throughout his eight-win, 14-year career, a status reflected in his being awarded the fan-voted Driver of the Day award despite his lowly finish.

"Typically the driver of the day is not something us drivers look too much into," Ricciardo admitted.

Ricciardo also pitted late to claim the fastest lap of the race, taking the extra world championship point away from race winner Lando Norris.

The Australian did not earn the point for himself — only by finishing inside the top eight can a driver add that to his championship total.

But by taking the point away from one former teammate in Norris as he challenges for the title, he helped another in Max Verstappen, who still leads the championship by 52 points.

"I don't mean this against Lando, but part of me is hoping Max wins by one point, because I think I guaranteed myself a nice Christmas present if so," Ricciardo joked.

For his part, Verstappen simply uttered "thanks Daniel" when told his ex-teammate had denied Norris the extra point.

A single point may not mean much in the larger scheme of things, but McLaren principle Andrea Stella said the move highlights an issue with Red Bull and its relationship with its sister team.

"I don't know the facts, I just saw that Racing Bulls went for the fastest lap and they achieved it," Stella said.

"But for me, talk about sportsmanship and so on, I think it would be out of place. I think we have to take it at face value that they scored the fastest lap and potentially as part of a longer-term conversation, we need to put the sport in a position in which, at any stage — being it trackside or being it factory side — teams behave in a totally autonomous manner. 

"Because this is a Constructors' Championship, a Drivers' Championship, it's not a coalition championship. Therefore, this needs to be definitely addressed.

"But at no point do I have elements now to say Racing Bulls went for the fastest lap to support Red Bull, I just find it a little peculiar."

Stella did say that he had "so much sympathy, support and friendship with Daniel" and he was "happy" that he got the accolade.