MOSCOW — Roberto Mancini was supposed to be the coach who turned Zenit St. Petersburg’s vast financial might into success on the field.

And if someone got in Mancini’s way, it was likely to be Massimo Carrera, another Italian coach who won the Russian title with Spartak Moscow last season.

What few counted on was a resurgence by a 70-year-old Russian coach and a team of journeyman players assembled for a fraction of Zenit’s transfer spending. But that’s exactly what happened Sunday as Yuri Syomin and Lokomotiv Moscow sliced through Zenit 3-0 in St. Petersburg to lead the Russian league at the halfway point of the 30-game season.

A well-organized defense and a healthy dose of luck helped Lokomotiv hold firm under wave after wave of Zenit attacks in the first half, before scoring on three incisive counterattacks in the second. Peru forward Jefferson Farfan, at 33, showed age hadn’t blunted his speed by scoring twice and setting up the third for talented young winger Alexei Miranchuk.

That leaves the Railwaymen three points clear of Zenit at the top, with CSKA Moscow another four points behind in third. Defending champion Spartak is in sixth after mixing European success — including a 5-1 Champions League rout over Sevilla — with lackluster performances in the Russian league.

A Soviet-era player who built his coaching reputation in part with jobs in far-flung locations like Tajikistan and New Zealand, Syomin won the Russian title with Lokomotiv in 2002 and 2004, but until recently his golden years looked long past.

Syomin more recently spent time in the Azerbaijani league and with Russian relegation-battlers before finishing eighth with Lokomotiv last season in his fourth spell as coach.

While Zenit spent the off-season signing Mancini and a raft of Argentine players, Syomin focused on hammering his veterans into a team.

That has paid off with this season’s title challenge based on strong organization in defense and attack — before Sunday’s game, Lokomotiv had scored almost half its goals from set pieces.

Syomin is reluctant to consider his team title contenders, though.

“Only Paul the Octopus could know what will happen next,” Syomin said, referring to the cephalopod who predicted results for the 2010 World Cup. “And he’s dead.”