When AC Milan striker Rafael Leao outmaneuvered the Sassuolo goalkeeper Andrea Consigli with a fierce shot after receiving an incisive pass from Hakan Calhanoglu on Sunday, every player and coaching staff at the Mapei Stadium was blown away by the extremely early breakthrough.

The 21-year-old Portuguese, who only plied his trade on the reserve team of Sporting CP three years ago, has put the league leaders ahead virtually from the kick-off and written his name into history. He scored the fastest ever goal in Serie A in 6.2 seconds, beating the record of 8.9 seconds set by Piacenza's Paolo Poggi against Fiorentina in 2001.

Leao's goal was also quicker than the fastest strike in Premier League history. Last year, Southampton's Shane Long netted after 7.69 seconds against Watford on April 23.

Milan coach Stefano Pioli later revealed in his post-game press briefing that Leao's move was rehearsed in training and it has a remarkable and miraculous effect during the Sassuolo game.  

"We have four or five possible situations for the kick-off which we alternate," he beamed. "We wanted to approach the game the right way from the start. We did very well to score after just six seconds and [Brahim] Diaz, Calhanoglu, and Leao made the right movements."  

Alexis Saelemaekers added a second following a powerful Theo Hernandez run in the 26th minute and Domenico Berardi pulled one back for Sassuolo late in the game from a deflected free-kick. 

Milan remain unbeaten after 13 games and lead the standings with 31 points, one ahead of Internazionale.

Inter needed second-half goals from Achraf Hakimi and their leading scorer Romelu Lukaku to overcome stubborn resistance from Spezia and win 2-1. 

Spezia held out until seven minutes into the second half when Hakimi latched on to Lautaro Martínez's pass, sped away and slipped the ball past Ivan Provedel. Lukaku added the second from a penalty in the 71st minute, after M’Bala Nzola handled. Roberto Piccoli pulled one back in stoppage time. 

Lazio brushed aside their dismal home form when goals from Ciro Immobile and Luis Alberto gave them a 2-0 win over Napoli. The hosts scored from their only two shots on target as Napoli slumped to a second defeat in five days after losing 1-0 at Inter. Napoli stayed fifth with 23 points, while Lazio are eighth with 21.

In England, Manchester United blitzed Leeds 6-2 to climb to third in the Premier League as Leicester put a major dent in Tottenham's title challenge. 

The first league battle in 16 years between bitter rivals United and Leeds was keenly anticipated, but Ole Gunnar Solskjaer's men proved far too strong at an empty Old Trafford. 

United, who made a stuttering start to the season, now have 26 points – five behind leaders Liverpool with a game in hand. They are a point adrift of second-placed Leicester, who beat Spurs 2-0 earlier to complete a miserable few days for Jose Mourinho, whose team  now find themselves all the way back in the fifth spot – six points adrift of the champions Liverpool. 

Sam Allardyce's return to the Premier League as West Brom manager got off to a terrible start as the Baggies were outclassed 3-0 by local rivals Aston Villa, who moved up to ninth. 

In Spain, Real Madrid's Karim Benzema kept up his impressive run of form by scoring and providing two assists in a 3-1 win away to Eibar, taking the champions level on points with La Liga leaders Atletico Madrid. 

Diego Simeone's Atletico have two games in hand, though, after Saturday's 3-1 success against Elche. Fifth-placed Barcelona are eight points adrift of the Madrid pair following their 2-2 draw this weekend with Valencia. 

In Germany, Borussia Monchengladbach forward Marcus Thuram has apologized for spitting in the face of the Hoffenheim defender Stefan Posch during Saturday's Bundesliga match. 

Thuram spat toward Posch during a confrontation, and the video assistant referee spotted the incident, prompting the referee to upgrade Thuram's yellow card to a red and send him off.

"Today something took place that is not in my character and must never happen," Thuram, son of France’s 1998 World Cup winner Lilian Thuram, wrote on Twitter. 

"I reacted to an opponent in a wrong way and something occurred accidentally and not intentionally. I apologise to everyone, to Stefan Posch, to my opponents, to my team mates, to my family and to all those who saw my reaction. Of course, I accept all the consequences of my gesture." 

Gladbach said in a statement on Sunday that they would fine Thuram, who faces a lengthy ban, and impose an internal suspension. 

In France, Lille moved back to the top of Ligue 1 after holding Paris Saint-Germain to an uninspiring goalless draw that failed to live up to its pre-match billing.  

Lille take first place in the French top-flight from Lyon on goal difference after a match that saw just a handful of shots on target and very little in the way of incident. 

PSG are a point back in third after failing to create anything from their territorial dominance, shorn of attacking inspiration without Neymar and Mauro Icardi, among others, while Kylian Mbappe started on the bench as he reportedly struggles with a thigh knock. 

Meanwhile, Marseille are five points behind the leaders after their 1-1 draw with Reims on Saturday, although Andre Villas-Boas' side have two games in hand on their title rivals. 

(With input from agencies)