A first-half header from Juan Cuadrado delivered a 1-0 win for a jittery Juventus at Sampdoria Sunday during which infuriated coach Massimiliano Allegri kicked kit bags on the touchline.
Juve's 24th league win of the campaign moved the champions 10 points clear of Napoli after their earlier 3-2 win at Empoli, while Roma can restore an eight-point deficit with a home win against Sassuolo later in the day.
But, days after sealing a mouthwatering Champions League quarter-final match-up with Barcelona following a 1-0 win over Porto, it was a far from trademark Juventus performance at the Luigi Ferraris stadium.
Cuadrado rose to meet a great delivery from Kwadwo Asamoah after just seven minutes to put Juve ahead, but after losing playmaker Paulo Dybala to injury early on the Turin giants laboured for the remainder.
Injuries in midfield and defence forced Allegri to ring the changes, Claudio Marchisio and Alex Sandro joining defenders Giorgio Chiellini on the bench while Leonardo Bonucci was rested to avoid a ban ahead of an upcoming clash with Napoli.
Asamoah started at left-back, and the Ghanaian seized the day with a great delivery that Cuadrado rose to head confidently past Christian Puggioni.
Stepping in for suspended Samp 'keeper Emiliano Viviani, Puggioni made amends by stopping Gonzalo Higuain from close range after the Argentine pounced on a Karol Linetty error.
But the 27th minute loss of Dybala, who hit the winner from the spot over Porto on Tuesday, due to a muscle problem upset Juve's plans.
Bruno Fernandes' volley tested Gianluigi Buffon in the Juve net while at the other end Puggioni flew to fingertip Pjaca's angled drive around the post on the stroke of half-time.
If Allegri hoped for improvement, he was to be left disappointed by a messy second half.
Former Juve striker Fabio Quagliarella tested Buffon five minutes after the interval, and at the other end Higuain was offside when he volleyed over over from six yards.
Allegri's nerves were frayed when Asamoah panicked while under pressure in the area, Samp regaining possession for a cross that saw Buffon forced into action at his far post.
On the counter, Luis Muriel cut inside Daniele Rugani to unselfishly slip through for Patrik Schlick, who tripped as he battled for possession with Asamoah.
The errors were piling up for Juve in attack too, Higuain collecting Pjaca's ball from the left only to overhit his pass for Cuadrado.
Cuadrado was replaced moments later by Mario Lemina, whose first task was to head clear a dangerous Quagliarella ball into the area.
Allegri was growing more frustrated, and erupted 12 minutes from the end when Dani Alves came off worst in a fair challenge with Vasco Regini.
A promising Lemina counter forced a corner, but Samp pressing saw Juve pushed back into their own area, where Asamoah had to scramble to recover under more pressure after momentarily losing possession.
Tired-looking and ineffective, Higuain was subbed five minutes from the end, Stephan Lichtsteiner coming on to move to the right of midfield.
It was Samp who finished on a high, although Quagliarella fired his overhead kick over the bar before Muriel was dispossessed from behind by Asamoah as he went on a promising run.
Elsewhere, Lazio's Champions League hopes were dented by a scoreless draw at Cagliari that left Simone Inzaghi's men in fourth but now five points behind Roma and six behind Napoli.
Inter, held 2-2 at Torino on Saturday, sit fifth at two points behind Lazio but on the same points (55) as Atalanta, who cruised to a 3-0 home win against Pescara.