Eberechi Eze got his first Arsenal goal as Mikel Arteta's men laboured to beat League One Port Vale 2-0 in the third round of the Carabao Cup.
After Eze struck just eight minutes into the match this should have turned into a comfortable night for the Gunners against a side who, despite back-to-back wins sit 19th in the third tier, but they struggled to create clear chances until substitute Leandro Trossard finished it off in the 86th minute.
Still it was enough for Arsenal, semi-finalists last season, to progress as they seek to win this competition for only a third time.
Roared on by the biggest Vale Park crowd this century, 16,326-strong, Port Vale came charging out of the traps in the opening five minutes, but no sooner had Arsenal got a foothold in the game they led through Eze's first goal since his £60million move from Crystal Palace.
Arsenal made the goal look easy as Bukayo Saka won back possession and switched play to the left. Myles Lewis-Skelly's dummy wrong-footed Jesse Debrah as Gabriel Martinelli's low ball left Eze with a simple close-range finish.
Eze was part of a strong Gunners side featuring nine changes from Sunday's 1-1 draw with Manchester City as Saka returned to the starting XI after a hamstring injury, Christian Norgaard made his first start and there was a debut in goal for Kepa Arrizabalaga.
The last time these two sides met 27 years ago Arsenal needed penalties to win an FA Cup third-round replay here, having been held goalless at Highbury, and despite Arsenal taking an early lead here this turned into another tough scrap against determined opposition.
For all their possession - 78 per cent in the first half - Arteta's men struggled to carve out clear opportunities as the hosts defended in numbers.
Just as they did in the first half, Port Vale start the second half on the front foot but they were then almost hit on the counter-attack as goalkeeper Joe Gauci had to come racing out of his box to take the ball from Martinelli's feet.
Having seen his side fail to build on their early lead, Arteta turned to 15-year-old Max Dowman, who replaced Saka just after the hour to chants of 'He's got school in the morning' from the 3,000 travelling Arsenal fans.
Viktor Gyokeres and Gabriel soon followed him into the fray but Arsenal's immediate concerns were at the back.
A wayward pass from Christhian Mosquera went straight to Ben Garrity on the edge of the Arsenal box. He laid it off for Rhys Walters, but a moment's hesitation allowed Arsenal to get back in numbers.
Next, substitute Devante Cole hit a dipping shot from the edge of the box that went narrowly over.
Gyokeres should have killed it off in the 78th minute, played through on goal by Dowman, but he took too long and Cam Humphreys slid in to block.
But then, with time running down, William Saliba launched a long ball forward which Trossard controlled neatly as he cut inside to beat Gauci with a low finish as home fans appealed in vain for what would have been a tight offside call.
