Five things we learned in European football this weekend

Fulham's Serbian striker Aleksandar Mitrovic (L) clashes with Tottenham Hotspur's Colombian defender Davinson Sanchez (R) during the English Premier League football match between Fulham and Tottenham Hotspur at Craven Cottage in London on January 20, 2019. AFP PHOTO

What you need to know:

  • Borussia Dortmund's 1-0 win at RB Leipzig saw the Bundesliga leaders start 2019 in the best manner possible, with Axel Witsel's strike keeping Lucien Favre's side six points clear of Bayern Munich.
  • A dire season for Monaco continued on Saturday as they suffered a humiliating 5-1 home defeat against Strasbourg, leaving them still three points from safety in Ligue 1.

Barcelona needed Lionel Messi to play the role of super sub as they maintained their five-point lead atop La Liga, while not all was rosy for Paris Saint-Germain despite a record-breaking home win on Saturday.
As Monaco plumbed new depths, and Borussia Dortmund kept their Bundesliga title push on track, AFP Sport looks at some of the main talking points from the weekend in Europe:

Barca can rotate, but need Messi
Ousmane Dembele excelled, but it was Lionel Messi's contribution that proved decisive as Barcelona beat Leganes 3-1, their seventh straight La Liga win keeping them five points clear of Atletico Madrid.
Barca coach Ernesto Valverde needs to rotate his squad in this busy period to keep players fresh for the Champions League knockout rounds.
On Sunday it was Messi's turn, the Argentine being left out of the starting line-up for the first time since his return from a broken arm in November.

But the Catalans were being held 1-1 when Messi came on in the 64th minute, and he duly made the second goal for Luis Suarez before sealing victory with his 18th league goal this season.
"There are lots of games," Valverde said. "We talk to the players and decide when it may be good for them to rest."

PSG crying out for a midfielder
It was quite a weekend for Paris Saint-Germain, who destroyed Ligue 1's bottom side Guingamp 9-0 to claim their record home win, with Edinson Cavani and Kylian Mbappe scoring hat-tricks.
Neymar also netted twice, and the Brazilian is flourishing under coach Thomas Tuchel -- "It's a friendship but, at the same time, a huge mutual respect," Neymar told Canal+ of their relationship.

Yet while their attack looks irresistible ahead of next month's Champions League clash with Manchester United, there are problems elsewhere.
Tuchel was already in desperate need of a new midfielder, especially with contract rebel Adrien Rabiot currently frozen out.
On Saturday, Marco Verratti -- his one remaining bona fide midfielder -- came off with an ankle injury, meaning the race is on for him to be fit for Old Trafford. Meanwhile, PSG have 10 days to sign a new midfielder, which could be Everton's Idrissa Gueye or Leandro Paredes of Zenit Saint Petersburg.

Henry needs to keep his cool
A dire season for Monaco continued on Saturday as they suffered a humiliating 5-1 home defeat against Strasbourg, leaving them still three points from safety in Ligue 1.
It was a home debut to forget for Cesc Fabregas, and coach Thierry Henry lost his cool, complaining that a faulty VAR system denied his team a penalty when the score was 2-1.
Henry was also caught mouthing an ugly insult to Strasbourg defender Kenny Lala, and he needs to keep his cool and quickly find a way of turning around Monaco's season.
"It was a reaction and I regret it, but I am human," admitted Henry, who has overseen just two wins in 12 league games.

Napoli not giving up
A relentless Juventus have won 17 and drawn two of 19 Serie A games as they chase an eighth straight title. Yet it is to Napoli's immense credit that the Turin team are not completely out of sight already.
Carlo Ancelotti's side were missing key players against Lazio on Sunday, but still won 2-1 with goals from Jose Callejon and Arkadiusz Milik.
A sixth win in seven league games means they are six points off top spot before Juve play Chievo on Monday.

Dortmund can win without Reus
Borussia Dortmund's 1-0 win at RB Leipzig saw the Bundesliga leaders start 2019 in the best manner possible, with Axel Witsel's strike keeping Lucien Favre's side six points clear of Bayern Munich.
The result proved they can pick up three points without influential playmaker and captain Marco Reus, who has scored 11 goals and claimed seven assists this campaign but missed Saturday's win through injury.
They host strugglers Hanover 96 next Saturday, and sporting director Michael Zorc expects Reus to be out for "one or two weeks maximum".