Marseille down Monaco with late penalty, Lyon score four
Earlier, Lille passed up the opportunity to move provisionally into third place in Ligue 1 after conceding a late equaliser to bottom side Montpellier.
After leaders Paris Saint-Germain drew on Saturday, it was the chance for the second- and third-placed sides to close the gap to the top.
And it was Marseille who took that chance with their slender win leapfrogging them above Monaco into second place on goal difference, the pair are tied on 26 points -- seven behind PSG.
Marseille coach Roberto De Zerbi told DAZN it was his side's "best match of the season at the Velodrome".
"We played a great game, especially as Monaco are a great team. But I'm sure we can do even better," the Italian added.
Aleksandr Golovin made the breakthrough for Monaco four minutes before half-time with a deflected finish.
But Marseille struck back in the 53rd minute through Luis Henrique.
A half-blocked cross appeared to be going behind but spun on the line to stay in at the near post and Neal Maupay reacted quickly to nod it across the goalmouth, where the Brazilian was on hand to head in his sixth goal of the season.
The decisive moment then came in the 87th minute when the referee adjudged that Monaco's Christian Mawissa had blocked a cross with his hand.
Greenwood duly sent the goalkeeper the wrong way to seal the comeback win for De Zerbi's side.
In Lyon, Lacazette scored twice in the first half, before putting the cherry on top for the home side with a 69th-minute penalty.
Sofiane Diop had equalised for Nice midway through the first period, before Lacazette and Jordan Veretout struck to open up a two-goal buffer by the interval.
Lyon move up to 22 points, two ahead of Nice in sixth place and one behind fourth-placed Lille.
Lacazette sent his side ahead on four minutes, poking home a cross at full stretch.
Nice hit back in the 22nd minute as Diop did well to reach Mohamed-Ali Cho's back-post cross.
Lacazette and Veretout scored in the 41st and 43rd minutes to restore Lyon's lead, before the former Arsenal forward made the points safe with a second-half spot-kick.
"This victory is good for us and rounds off a great week," said Lacazette, after Lyon also won by the same scoreline against Azeri side Qarabag in the Europa League on Thursday.
'Anything is possible'
Earlier, Jonathan David twice gave Lille the lead from the penalty spot in either half but Issiaga Sylla struck in first-half injury time and Arnaud Nordin then found a 93rd-minute leveller for Montpellier as the points were shared in a 2-2 draw.
"We offered far too little to be more dangerous (in the second half), to create more situations for ourselves and to put ourselves in the clear," said Lille coach Bruno Genesio.
"We know that in this kind of match, anything is possible right up to the end."
Lille sit three points behind third-placed Monaco, while Montpellier stay rooted to the foot of the table, five points from safety.
David broke the deadlock in the 44th minute as he sent Benjamin Lecomte the wrong way from 12 yards.
The lead only lasted three minutes with Sylla glancing home a corner on the stroke of half-time.
The Canadian restored Lille's lead from the spot nine minutes into the second half but late on they failed to clear the danger from a cross and Nordin finished gleefully from close range.
Montpellier forward Tanguy Coulibaly was sent off in the 99th minute for firing the ball at Genesio after a foul was given against him.
In the chaotic aftermath of the incident, Lille substitute Mitchel Bakker was also given his marching orders.
Eighth-placed Auxerre went down 2-0 at Toulouse thanks to two goals in seven first-half minutes from Joshua King and a Vincent Sierro penalty.
Angers took an invaluable three points in the relegation battle with a 1-0 win against Le Havre, who dropped into 16th spot.