Juventus clinched their fourth straight Serie A title after a hard-fought victory over Sampdoria secured courtesy of Arturo Vidal’s first-half header. The Turin club needed only a point at the Luigi Ferraris Stadium to win their 31st Scudetto but got all three. Chile midfielder Vidal scored the decisive goal when he met Stephan Lichtsteiner’s cross to head in. It handed Juve boss Massimiliano Allegri the title in his first season in charge of the club. Allegri, 47, was appointed Juventus coach last summer after Antonio Conte quit the club a day after his players returned for pre-season. Conte, now managing the Italian national team, said he left because it “may be more difficult to keep winning with Juventus” in the future. But ex-Milan boss Allegri has not struggled in his debut season with the Old Lady. Juve wrapped up the title, ahead of second-placed Lazio, with four games of the season remaining, having lost just three times in this campaign to date. Vidal found the net just after the half-hour mark when, unmarked at the back post, he got on the end of Lichtsteiner’s ball from the right and planted a header back across goal and into the net. Allegri, who also won the Serie A title in his first season in charge of Milan in 2010-11, will now attempt to complete a treble with Juventus in the rest of the campaign. Juve face European Cup holders Real Madrid in the first leg of their Champions League semi-final on Tuesday, and also play Lazio in the Italian Cup final.