Oliver McBurnie marked his Swansea City debut with a brace as Francesco Guidolin's side beat Peterborough United 3-1 in the EFL Cup second round at the ABAX Stadium.
In a convincing victory, the Swans were ahead after 15 minutes via Jay Fulton, who headed home his first goal for the club after McBurnie set him up.
Then the 20-year-old striker took his chances with two goals in three minutes.
First, he raced onto a through ball before cutting inside and slotting home.
Then he blasted into the net from close range after fellow debutant Mike van der Hoorn was denied by keeper Mark Tyler.
Sub Leo Da Silva Lopes fired in a thunderous consolation goal for the League One hosts, but the Swans comfortably moved into the third round.
The Swans made ten changes to the starting XI.
Francesco Guidolin handed debuts to summer signing Mike van der Hoorn and striker Oliver McBurnie, while Nathan Dyer made his first start this season since returning from a loan spell at Leicester City.
Neil Taylor got his first taste of action since his successful Euro 2016 campaign with Wales while Angel Rangel was included in the starting XI for the first time this season.
Swedish international Kristoffer Nordfeldt was named in goal while, in midfield, Leon Britton returned to captain the side after missing the Tigers loss via illness. Ki Sung-Yueng, who came off the bench last weekend, joined Britton in midfield along with Jay Fulton.
The final change saw Jefferson Montero provide pace and width as the Ecuadorian made his first start of the campaign.
The League One hosts included former Swans winger Gwion Edwards in their starting line-up, with the Lampeter product going into the game having scored three goals in his last four league games.
There was a late change between the sticks for Peterborough as Mark Tyler started in place of Ben Alnwick, who picked up an injury before kick-off.
PETERBOROUGH: Mark Tyler, Michael Smith, Andrew Hughes, Michael Bostwick, Gwion Edwards, Chris Forrester (capt, Callum Chettle, 74), Paul Taylor (Shaquile Coulthirst, 65), Marcus Maddison, Ricardo Almeida Santos, Jermaine Anderson (Leo Da Silva Lopes, 58), Tom Nichols.
SUBS: Dion-Curtis Henry, Joe Gomley, Hayden White, Jerome Binnon-Williams.
SWANS: Kristoffer Nordfeldt, Angel Rangel, Mike van der Hoorn, Jordi Amat (Federico Fernandez, ht), Neil Taylor, Leon Britton (capt, Leroy Fer, 79), Jay Fulton, Ki Sung-Yueng, Nathan Dyer, Jefferson Montero, Oliver McBurnie (Fernando Llorente, 65).
SUBS: Gerhard Tremmel, Kyle Naughton, Gylfi Sigurdsson, Modou Barrow.
The Swans showed their intentions from the start, with Jefferson Montero at the heart of the attacks.
His blistering pace caused problems for Peterborough as early as the ninth minute, with the winger racing past his marker before his cross was nodded over the crossbar six yards out. From the resulting quickly-taken corner, Montero's fierce drive clipped the crossbar and bounced over with Mark Tyler beaten.
Montero was at it again shortly after. Again he outpaced his marker before squaring for Oliver McBurnie, but the Scottish striker headed wide.
The Swans kept up the pace, and they went close again through McBurnie, who fired wide on the turn after being teed up by Jay Fulton.
At the other end, during a brief respite, ex-Swan Gwion Edwards blasted over from 20 yards when he found himself in a yard of space.
But the Swans were soon ahead as, after 15 minutes, Montero crossed for McBurnie, and when his initial effort was saved, the striker nodded across goal to Fulton, and he headed in from close range.
The visitors were probing again via Montero, who raced down the left after being fed by McBurnie. The Ecuadorian's cross dropped perfectly outside the box for Dyer, but his first-time volley was comfortably gathered by Tyler.
The Swans were relentless, and Dyer should have doubled the lead when he latched onto Fulton's pass over the top. But the winger, one on one wiht Tyler, was denied by the legs of the Posh keeper.
The chances kept coming, and a golden opportunity to make it 2-0 went begging as another through ball sent Dyer in on goal. This time he scuffed his shot wide of the far post.
Ki Sung-Yueng was the next to try his luck, but the South Korean was denied low down by Tyler after he cut inside the box from the left flank and let rip.
The Swans kept pushing though, and this time it was the post that denied them as Montero twisted and turned his marker in the box before his shot was nudged onto the woodwork by Tyler.
But seconds later, the Swans did double their lead.
McBurnie raced onto a through ball and he kept his composure by cutting back inside before slotting his shot inside the near post after 41 minutes.
Two minutes later it was 3-0 as McBurnie netted his second.
Again the Swans broke the offside trap, and after setting up the supporting Mike van der Hoorn - who saw his shot parried by Tyler - McBurnie latched onto the loose and blasted home from four yards.
HALF-TIME: Peterborough 0 Swans 3
Francesco Guidolin made a change at the break with Federico Fernandez replacing Jordi Amat in defence.
And the Argentinian was straight into the action as he slid in to take the sting out of Marcus Maddison's effort just seconds into the second half.
The game hit a lull period, with McBurnie's 64th-minute effort the only real action following that.
It proved McBurnie's final act as he was replaced by Fernando Llorente a minute later.
Llorente was soon among the action as he latched onto a through ball. After holding play up, he touched to Dyer via Fulton, and the former's effort squirmed just wide of the far post.
Kristoffer Nordfeldt was then called into action to pull off two saves in succession as he twice denied Tom Nichols.
And the home fans were on their feet in the 75th minute as sub Leo Da Silva Lopes cut the deficit to 3-1 when he fired a thunderous effort from 20 yards which gave Nordfeldt no chance.
The Swans almost replied immediately through Llorente, who met Montero's cross, but his header was deflected wide from close range by sub Shaquile Coulthirst.
But there was drama to come, with Posh striker Tom Nichols going close to making it 3-2 but his powerful effort beat Nordfeldt but not the near post as it cannoned off the woodwork.
That was the end of the action though as the Swans booked their place in the third round.