Albert Luque staked his claim for a place in Sam Allardyce's new-look Newcastle side after scoring twice in the 4-1 friendly against Celtic.
Luque (r) managed to score just two goals last season
Luque, who has scored just one Premier League goal in two seasons, struck twice in the first-half after Obafemi Martins gave Newcastle an early lead.
Celtic's new signing Scott Brown pulled a goal back for the Scottish champions in the second half.
But James Milner's late strike restored the Magpies' three-goal advantage.
Newcastle paid £9.5m for Luque in 2005, but he has struggled to settle.
Last season he managed to score just twice for the Magpies, with both goals coming in the club's Uefa Cup campaign.
After the game Allardyce revealed Luque has been working hard in pre-season training.
"We're just trying to get him fitter," said the Newcastle boss.
"If we can get him fitter he'll feel better physically - and then he'll feel better mentally.
"It's up to him whether he wants to continue going through the pain barrier as he has over the last few days."
A crowd of 30,225 attended the game, including former Magpies boss Sir Bobby Robson.