DOHA, Qatar -- They were crowned champions of Europe on June 1 and now, on Dec. 21, they're champions of the world. When Liverpool finally look back on 2019, it will go down as a pretty good year, especially if it proves to be the one that laid the foundations for them to become champions of England for the first time since 1990.

- Report: Liverpool win Club World Cup for first time

Roberto Firmino's goal in extra time, following a hard-fought FIFA Club World Cup final against Brazilian side Flamengo in Qatar, was enough to secure a 1-0 victory and make Liverpool world champions for the first time. Just six months after the club's sixth Champions League triumph, earned with a win against Tottenham in Madrid, Liverpool finally added the world title to their honours list after three previous failures in 1981 vs. Flamengo, 1984 vs. Independiente and, back in 2005, vs. Sao Paulo. Previously, Manchester United had been the only English club to have earned the distinction of being crowned world champions, in 1999 and 2008, but Liverpool now have one of the trophies that has eluded them for so long.

"We couldn't do more tonight than win this game for the first time for this wonderful club," manager Jurgen Klopp said following the win.

"It was outstanding. I am so proud of the boys. It's a wonderful night for us and everyone who is with us. Flamengo should be proud of what their team did, but I think we deserved to win -- we were the better side."

After such an incredible year, few could argue with their new status as the best team in the world. So far in 2019, they've played 56 games, won three trophies, ended one long wait for victory and have positioned themselves to end another, in the Premier League, thanks to their performances over the past four months.

Liverpool have not been beaten in the Premier League since Jan. 3 -- their first game of the year -- when they lost 2-1 at Manchester City. At the end of the season, that sole defeat proved decisive in settling the Premier League title in Man City's favour ahead of Liverpool's. In Europe, Liverpool overcame the might of Bayern Munich and Barcelona, the latter unforgettably so by winning the semifinal second leg 4-0 at Anfield, on the way to beating Tottenham in the final, and they went on to add to that success by beating Chelsea in the UEFA Super Cup in Istanbul in August. By the time Klopp and his players arrived in Doha for the Club World Cup last Sunday, they had already become intoxicated by the taste of success.

Jurgen Klopp has brought a winning culture to Liverpool, but 2019's brilliance is just the start of their journey. John Powell/Liverpool FC via Getty Images

In England, this competition does not enjoy the status it perhaps deserves, considering the title that comes with it and the success you must enjoy to qualify for it in the first place. But when a team starts to win trophies, the next step is making it a conveyor belt bringing regular silverware, which is where Klopp's Liverpool find themselves now.

It seems an age ago since Klopp and his players were dismissed as perpetual runners-up, having lost finals in the Champions League, Europa League and League Cup during his early years in charge. Last year's near miss in the Premier League, after banking 97 points as runners-up, has been used as a springboard for an assault on this year's title rather than as a setback in which to wallow with self-pity. Winning the Champions League, UEFA Super Cup and Club World Cup has turned Liverpool into serial winners, and this success in Doha is unlikely to be their last this season.

Liverpool face second-place Leicester at the King Power Stadium on Thursday, 10 points clear of Brendan Rodgers' team having played one game fewer and with the Foxes coming off a chastening 3-1 defeat at Manchester City. A win over their closest challengers would ensure that the second half of this season becomes little more than a procession for Liverpool as they finally end a 30-year wait for a domestic title.

And who knows? Perhaps a first FA Cup success since 2006 is also on the cards if they beat neighbours Everton at Anfield in the third round next month. With the Champions League to defend too, having been drawn to face Atletico Madrid in the last 16, Liverpool are well-placed to continue their trophy haul in 2020. But 2019 will go down as the year that made it happen.

Liverpool started the calendar year with questions to answer, but they have responded emphatically. If they win, and win again, from this point on, it will be because of what happened in 2019.