Sergej Milinkovic-Savic completed a second-half turnaround as Lazio secured what could be a crucial win in the Serie A title race by beating Inter 2-1 at the Stadio Olimpico.

Lazio fell behind to Ashley Young's first goal since joining Inter in January but rallied after the restart to hand Antonio Conte's side, who went into this weekend top of the table, their first top-flight defeat in 17 matches.

Inter centre-back Stefan de Vrij, whistled incessantly by fans of his former club, was deemed to have fouled Ciro Immobile in the box and the prolific striker made no mistake from the spot five minutes into the second period.

Sergej Milinkovic-Savic gave Lazio the lead with 21 minutes remaining and the hosts held on to move up to second, two points ahead of Inter and one behind leaders Juventus.

Lazio were without Milinkovic-Savic in their 1-0 win over Parma last weekend due to suspension and the Serbia international almost made a significant impact within nine minutes of his return, producing a venomous 20-yard drive that hit the crossbar.

Inter's best moments came on the break and after Thomas Strakosha blocked Antonio Candreva's swerving effort Young volleyed the follow-up into the top-left corner in the 44th minute.

Lazio were level five minutes after the restart. Milan Skriniar intercepted Luis Alberto's pass but looped it over Daniele Padelli, who fell over him, and De Vrij was penalised for a push on Immobile, who slotted home the resulting penalty.

Young was disappointed not to be awarded a spot-kick when he went down under a challenge from Luiz Felipe and Inter fell behind in the 69th minute.

Marcelo Brozovic did well to block Adam Marusic's shot on the line but Milinkovic-Savic picked out the bottom-left corner with the next attempt.

Lautaro Martinez headed in a Young cross from an offside position as Inter pushed for an equalizer, while Immobile was denied a brilliant second by Padelli as Simone Inzaghi's side extended their unbeaten run in Serie A to 19 matches.

What does it mean? Lazio are serious challengers

Two draws in their previous four matches had seen Lazio fail to take full advantage of slip-ups from fellow title challengers Inter and Juve.

This win ensured they remain thoroughly in contention, and while Inter and Juve have European and Coppa Italia commitments in their schedule, Lazio can focus all their attention on winning a first Scudetto since 2000.

Unstoppable Immobile

Immobile was in danger of failing to score in three straight Serie A games for the first time this season but by firing home from the penalty spot he took his tally for the campaign to 26.

De Vrij slips up

His first touch – and every subsequent one – was met with a chorus of boos and, after a decent first half, the former Lazio player gave away the penalty that the hosts equalized from.

What's next?

Inter head to Bulgaria for the first leg of their Europa League last-32 tie against Ludogorets on Thursday and entertain Sampdoria three days later. Lazio travel to Genoa next Sunday.