Five things we learned in Serie A

Here are five tings we learned in Serie A this week.

It's a two-horse title race

Perennial title hopefuls Napoli had gone 14 games without defeat in Serie A, but less than a week after suffering a 3-1 reverse to Real Madrid in the Champions League Maurizio Sarri's men saw their chances of challenging for a first scudetto since 1990 virtually snuffed out by a shock 2-0 defeat at home to unheralded Atalanta on Saturday. It left Napoli in third place but the Azzurri are now 12 points off the pace. Securing a top three finish that would offer the chance of Champions League football next season is now the focus for Napoli, who host Roma next week under pressure to hold on to third spot. Atalanta are only three points off the pace in fourth, with Lazio in fifth at five behind.

Is 'Ninja' Nainggolan the new Totti ?

Since his move to Roma from Cagliari three years ago, Radja Nainggolan has grown to become one of the capital side's most coveted players. Now, the Belgium international is being talked of as the new Francesco Totti - the emblematic club legend who over the years gained a reputation changing the outcome of games with one magical move or goal. Totti, now in his 25th and likely final season at the club, sat on the bench throughout on Sunday as Nainggolan struck two spectacular goals either side of half-time to almost singlehandedly send Roma towards their first single-season double-win over Inter since 1995.

Bacca goal, and assist, an internet hit

With only eight league goals prior to securing the points from a 1-0 win at Sassuolo, Carlos Bacca has been underwhelming for AC Milan so far. But the Colombia striker's mis-hit penalty strike at the Mapei Stadium on Sunday earned him plaudits, as well as a few quips, from fans across social media claiming he should be credited with an assist as well as the goal. One caption on a picture of Bacca said: "Makes his own assist for the goal, but doesn't get the credit." Sassuolo's players protested vociferously when Bacca appeared to first nudge the ball with his left foot before sliding to the turf and striking with his right to beat Andrea Consigli in the hosts' goal. Even Milan coach Vincenzo Montella conceded: "The penalty should probably have been taken again." The referee waved away the protests, and the goal, without the assist stood.

Borriello's 15th sparks Vieri holiday pledge

When former Roma striker Marco Borriello joined Cagliari at the start of the season, close friend and former Inter Milan striker Cristian Vieri sent a promise by video message which said: "Dear Marco, if you score 15 goals or more this season I'll pay for your holidays." It could soon be time to honour the pledge after Borriello hit the winner for the Sardinians in a 2-1 defeat of Crotone, the striker's 15th goal of the season and 11th in the league for Cagliari, who sit 12th at 35 points behind leaders Juventus.

Wham bam, thank you Ntcham

Genoa midfielder Olivier Ntcham had been used sparingly by the Serie A strugglers under the helm of Ivan Juric after joining the club on a two-year loan deal from Manchester City in 2015. But the 21-year-old Frenchman boosted his bid for more match time, following the sacking of Juric in midweek, with a sensational late strike that secured a point from a 1-1 draw at home to Bologna. Ntcham, who has been likened to former Juventus midfielder Paul Pogba -- who also played for France through the youth levels -- had made only nine appearances this season prior to Sunday. New Genoa coach Andrea Mandorlini looked resigned to defeat in his opening game after Federico Viviani's 57th minute strike for Bologna. But Mandorlini sent Ntcham on to replace Oscar Hiljemark in the 92nd minute and the former France under-16 captain had Genoa level two minutes later with a cracking strike from the edge of the area.