Juventus were denied the record for the fastest title success in Serie A history as a much-changed side fell to a 2-1 defeat at SPAL on Saturday.

Coach Massimiliano Allegri rested most of his key players with an eye on the second leg of their Champions League quarter-final against Ajax, but his young team failed to get the job done.

Moise Kean put Juve in front in the first half, turning in a shot from Joao Cancelo to score for the fourth straight Serie A game, the 19-year-old becoming the youngest player to do so in the era of three points for a win.

Kevin Bonifazi levelled with a header after the break, though, and SPAL skipper Sergio Floccari finished well to give his side a massive boost in their fight against relegation.

Juve's experimental line-up initially struggled and SPAL, who have now won their last three home league games, enjoyed the better of the opening exchanges before Juve took the lead on the half-hour mark.

A shot from Cancelo looked to be comfortable work for Emiliano Viviano but Kean was on hand to divert the ball away from the SPAL goalkeeper to surpass Mario Balotelli's Serie A record.

SPAL set about spoiling Juve's party by equalising in the 49th minute, Bonifazi getting up highest to head home Pasquale Schiattarella's right-wing corner.

Juve substitute Hans Nicolussi Caviglia forced a fine save from Viviano with a 20-yard curling drive, with Kean making way for Stephy Mavididi, indicating Allegri felt Juve had done enough.

He was badly mistaken, however, as SPAL took the lead through Floccari, who steered home after excellent work in the build-up from Alessandro Murgia.

Allegri sent on Federico Bernardeschi but Juve, who are 20 points clear at the top, could not find a leveller, with Mattia De Sciglio missing a header in stoppage time – and if Napoli win at Chievo on Sunday the title race will remain alive for a little longer.

What does it mean? Attention on Ajax costs Juve

Juve have known for some time that they will win the league again, with second-placed Napoli unable to exert as much pressure as they did last season under Maurizio Sarri.

Allegri therefore unsurprisingly had an eye on Ajax and his big names should be fresh for that game after sitting out the trip to SPAL, who moved seven points clear of the relegation zone.

Juve will now be watching Napoli's game on Sunday to see if they will be crowned champions this weekend. 

Kean makes his mark

Back in January, clubs including AC Milan were close to signing Kean on loan, but Juve opted to keep him at the club despite the fact he was rarely involved in the first half of the season.

That decision continues to pay dividends as Kean proves an able deputy – and potential successor – for Cristiano Ronaldo, breaking a Serie A record with a clever finish that showed his poacher's instinct in front of goal.

And, had Allegri kept the teenager on, Juve might well have been able to open the champagne.

Barzagli shows his age

At 37, Andrea Barzagli is easily old enough to be the father of some of his team-mates, such as 17-year-old debutant Paolo Gozzi, but his experience could not see Juve through and he looked to be at least partly at fault for both SPAL goals.

What's next?

Ronaldo and Juve's other stars will return on Tuesday when they host Ajax in the second leg of the Champions League quarter-final. SPAL go to fellow strugglers Empoli on Saturday, when Juve could celebrate winning the league in front of their own fans against Fiorentina.