Roma coach Jose Mourinho (second from left) celebrates with Gianluca Mancini on Sunday in Rome, Italy. Photo: VCG

Jose Mourinho said he felt like a child when charging from his dugout to celebrate Stephan El Shaarawy's last-gasp winner in a thrilling 2-1 victory over Sassuolo, which put his side top of Serie A in his 1,000th match as a manager.

Italy international El Shaarawy struck with a sublime curling strike in the 91st minute which caused wild celebrations at the Stadio Olimpico in Rome, with Mourinho running to join his joyous players in front of screaming supporters behind the goal.

"Today I wasn't 58 years old, I felt like a 10, 12, 14-year-old, back when you begin to dream about a career in football. It was a child's run," Mourinho told DAZN.

"During the week I lied to myself because I tried to convince myself that wasn't a special match but it was a special match... For the rest of my life I will remember that the match that took me to 1,000 was this one."

Jose Mourinho reacts during the match between Roma and Sassuolo. Photo: VCG

A breathless contest looked to be heading for a draw after Bryan Cristante's 37th-minute opener was canceled out by Filip Djuricic just before the hour mark and both sides wasted a raft of chances.

Tammy Abraham and Hamed Traore hit the post for each team but it was Roma goalkeeper Rui Patricio who had to be at his best to stop gilt-edged opportunities presented to Domenico Berardi and Jeremie Boga as Sassuolo pushed for a win.

With the seconds ticking away, El Shaarawy crashed in his shot from the edge of the area off the post to put Roma top, level on a perfect nine points with AC Milan and Napoli.

There was even time for a scare right after the winner when Gianluca Scamacca's wonderful strike was disallowed for offside to enormous roars from the home crowd.

"It was a match that could have finished 6-6, 7-7, they could have won 2-1 as we did," added Mourinho. 

"In the final 20 minutes Rui Patricio made two or three incredible saves, we missed chances practically in front of an open goal. I think that for the neutral it was an incredible match."

Milan are level with Roma thanks to a 2-0 win over Lazio which came through goals from Rafael Leao and Zlatan Ibrahimovic, who scored seven minutes after making his comeback as a second-half substitute following four months out of action.

The Swedish star, who turns 40 in three weeks, rolled home the simplest of finishes from Ante Rebic's low cross in the 67th minute to banish a knee injury he suffered at the end of last season, ensuring his second-placed team went two points ahead of reigning champions Inter Milan and Udinese.

Milan were the better team on a glorious late summer's evening at the San Siro and would have won even more convincingly had Franck Kessie not hit the bar from the penalty spot in first-half stoppage time.

They are three points ahead of Lazio, who sit sixth after their first defeat under new coach Maurizio Sarri. Milan now turn their attentions to Anfield and Wednesday night's opening Champions League clash with Liverpool.