Two goals in the opening seven minutes helped Newcastle secure a 3-1 first-leg advantage against Slovakian side Dubnica in the third round of the Intertoto Cup.
James Milner lobbed an excellent third midway through the second half to cap a fine personal performance - but Dubnica played well for spells and Lukas Tesak's strike just before half-time will give them hope for the second leg at St James' Park next week.
The departures of Patrick Kluivert and Craig Bellamy, and an injury to Shola Ameobi, had allowed 21-year-old striker Chopra a chance to impress manager Graeme Souness.
And the youngster wasted little time, latching onto an excellent pass from Milner before slotting past the advancing Dubnica goalkeeper Dusan Pernis.
The hosts, competing in the biggest game in their 79-year history, looked stunned by the early strike but soon found themselves two behind.
An awkward cross from the left by tricky winger Charles N'Zogbia caused confusion in the home defence, deflecting off centre-back Robert Novak and goalwards - with Shearer waiting on the back post to double the lead.
To their credit, the hosts did not buckle under the early pressure and forced their way back into the game late in the first half.
The impressive Igor Drzik, excelling against a Magpies midfield without new signings Scott Parker or Emre Belezoglu, floated in a delicate cross from the right, allowing Tesak to crash home a header from close range.
The complexion of the game could have changed completely early in the second period but for a smart save by Newcastle keeper Steve Harper from a Marian Zimen rocket.
But when Milner made room and lifted a superb side-footed shot over the stranded Pernis from all of 35 yards in the 70th minute, victory was secured.
