(Reuters) -Inter Milan's eight-match winning run in Serie A came to an end as two of their former players, Antonio Candreva and Keita Balde Diao, struck to give Sampdoria a shock 2-1 win in Genoa on Wednesday.
Candreva converted from the penalty spot before Keita guided home a finish to give the hosts a two-goal lead at the interval, and a Stefan De Vrij header was all Inter could muster in response.
Alexis Sanchez had a penalty saved early on but Inter struggled to threaten in the absence of striker Romelu Lukaku, who was only fit enough to feature for the final half hour and couldn't inspire a comeback.
The result left Antonio Conte frustrated as his side squandered the chance to go top of the table ahead of AC Milan, who play Juventus later on Wednesday.
“It was a strange match,” Conte said to Sky Italia.
“Sometimes you lose games like this, where you don’t deserve it.”
Inter remain second on 36 points, one behind their city rivals, while Sampdoria are 11th on 20 points.
Penalties dominated the opening stages as Inter were awarded one for handball following a Video Assistant Referee (VAR) review, which Emil Audero saved, before the same offence at the other end gave Candreva the chance to score against his former employers.
The hosts hit the bar through a Lorenzo Tonelli header, and Keita then doubled their advantage on the 38th minute after some excellent work by Mikkel Damsgaard to find the space to set him up with a cross.
Conte threw on attackers in search of a response as Ivan Perisic, Lukaku and Christian Eriksen were introduced, but De Vrij’s header from a corner was their only breakthrough.
Lukaku picked up a muscular problem in Sunday’s 6-2 win against Crotone and was lacking fitness, but he managed to draw a sharp save from Audero with a header.
“It wasn’t the first time we’ve played without Romelu, even though he’s obviously a quality player,” Conte said.
“He wasn’t at 100 percent and you could see that when he came on."
Inter face AS Roma next, who moved three points behind the Milan club with a 3-1 win at Crotone.
(Reporting by Alasdair MackenzieEditing by Christian Radnedge and Toby Davis)