Inter Milan were unable to impress new owner Erick Thohir with victory at San Siro as Renan scored at the death to salvage a 1-1 draw for Sampdoria.
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The Indonesian billionaire purchased a 70 percent stake in the Milan giants in October, ending oil tycoon Massimo Moratti's long-term tenure as president, but had until this weekend been unable to watch the Nerazzurri in action on home turf.
Fredy Guarin fired the hosts ahead in the 18th minute after some spellbinding dribbling from Ricky Alvarez, but Inter struggled to make their early dominance count and struggled to restrain an enthusiastic Samp side.
Visiting coach Sinisa Mihajlovic - an Inter player for two seasons before working as assistant coach to Roberto Mancini - finally unlocked his former club's defence by throwing on substitute Renan, who spared his club from suffering a fourth defeat in five games with his well-taken equaliser.
Eder, Roberto Soriano and Manolo Gabbiadini all went close as Samp dominated the early exchanges, but Guarin soon started causing problems for the home defence with his skill on the ball.
The Colombian could not get any real purchase on several speculative shots from outside the area, however, and would need a helping hand from a fellow playmaker.
Alvarez, who had been released down the left by Rodrigo Palacio, dazzled as he twisted and turned in the area before slamming the ball across the six-yard box to the waiting Guarin, who smashed it into the roof of the net.
Inter could have doubled their lead almost immediately, but Jonathan's right-footed effort veered past a post, and Samp responded quickly with Gabbiadini forcing a low block from Samir Handanovic.
It was a nervous end to the first half for the Slovenian goalkeeper, who had to look particularly lively when Angelo Palombo's corner took a wicked deflection in the box.
Samp rallied after the interval, Gabbiadini digging out a rasping shot from distance that tested Handanovic's reflexes.
Javier Zanetti, 40 years old and making his first start for Inter since suffering tendon damage in April, went for a second goal on the hour mark, Lorenzo De Silvestri bravely blocking the on-target strike.
The end-to-end dynamic continued with Handanovic called upon to repel a daisycutter from Eder before Samp substitute Gianluca Sansone saw his tricky effort saved.
As time wore on Inter grew wearier in the face of repeated visiting raids forward and concerned coach Walter Mazzarri urged his players to retreat for the final 10 minutes.
Mihajlovic responded to that tactical switch by replacing the struggling Pedro Obiang with Brazilian midfielder Renan, and the decision paid immediate dividends.
Renan had only been on the pitch for three minutes when he spotted a gap in Inter's defence before looking up and steering a superb left-footed curler past Handanovic to rescue a point.
Samp do, however, remain one point adrift of 17th-placed Bologna in the relegation zone. While Inter missed the chance to take third place from Napoli, they are three points clear of Champions League rivals Fiorentina.