The best teams make football look easy and Celtic did just that as Daizen Maeda, Yang and Luke McCowan shot down Raith Rovers in style.
It took the Hoops just over five minutes to open the scoring and it was on-fire Maeda, leading the line, who got it. He set the tone for a comfortable afternoon when he stroked one in from the edge of the box with his left foot.
The second took its time in coming but it was Maeda again who got it just before the break. And after Luke McCowan made it three within minutes of the restart, it was looking hairy for Barry Robson's team who didn't have an answer to the champions' dominance.
Yang went on to add a fourth before Maeda got a hattrick late on, with ref Chris Graham taking mercy on the visitors and blowing right on 90 minutes with no added time. It was as comfortable as you like for the Hoops as Brendan Rodgers' men now look ahead to their blockbuster Champions League showdown with Bayern Munich on Wednesday night.
Here's how it all unfolded.
Key Events
"It is the worst time you can lose goals in a game"
Defeated Raith boss Barry Robson admits the timing of the goals conceded in their 5-0 loss to Celtic was crushing.
Speaking to Premier Sports, he said:
You lose a goal within six minutes, another one two minutes before half time and then two minutes after half-time. It is the worst time you can lose goals in a game.
That affected us. They are flying high at the minute and are full of top players and it was a difficult game for us. But I thought we could have pressed the ball a wee bit better.
"Maeda's been on fire"
Celtic skipper Callum McGregor has lauded praise on hat trick hero Maeda.
He told Premier Sports:
Maeda's been on fire, what a season he's had.
He's got that hunger to score to get in at the backpost. His finishes were immense today. He wants more and so do we.
We've built a really strong squad, everyone's fighting. Even with nine changes today, there were a lot of top performances and the most important thing is people are hungry.
We're in a good place and in order to stay there we need to keep working hard.
Talking points
Here are our three talking points from tonight's clash in Glasgow's East End as Daizen Maeda steals the show.
FT! Celtic 5 Raith 0
No added time here as Maeda's hattrick and strikes from McCowan and Yang send Celtic through!
The holders are looking good and go into the hat for the draw.
Stick with us for the reaction!
Maeda announced as man of the match
No surprises there!
A well earned honour from the hattrick hero and he'll be a miss during the week against Bayern Muncih as he serves the second game of a Euro suspension.
Clinical stuff!
A word for Dane Murray
He'll have busier games if he is to make it as a Celtic player but Danr Murray hasn't looked out of place for a second here.
An assured performance from the 21-year-old who is making his case for a permanent spot in the squad.
21 goals in 34 appearances
An incredible return from Maeda whose stunning season only goes from strength to strength.
Into the final ten here!
GOAL! Maeda gets his hattrick
Hawaii Five-Oh blares out as Maeda arrives at the back post and bundles in the hattrick!
A great assist from Luke McCowan who charges forward and crosses from the left and Maeda was never not getting on the end of it.
Game over? Yeah, probably...
Nawrocki on for Schlupp
A job well done for Jeffrey Schlupp on his first Celtic start and he heads off for the final 18 minutes.
Maik Nawrocki comes on for a rare appearance with Liam Scales, wearing the captain's armband, set to finish the game at left-back.
An interested observer
A weekend off for Brentford who are already out of the FA Cup.
So look who's watching on from the stands here?
Kristoffer Ajer will be impressed with what he's seen from the men in green and white!
3 changes for Celtic
Changes just after the hour mark for Celtic as Nicolas Kuhn, Callum McGregor and Yang make way.
On come Jota, Arne Engels and Johnny Kenny.
£20m of talent come off the Celtic bench and Barry Robson is looking through his fingers.
GOAL! 4-0 Celtic as Yang gets in on the fun
And now it's getting hairy for the visitors.
Yang arrives at the back post after a brilliant cross from Anthony Ralston and gets in on the fun.
Still more than half an hour to go here but we can say, with confidence, Celtic are heading through.
Jota heads out for warmup
One of the biggest cheers of the afternoon as Jota heads out for a vigorous warmup.
There's no mercy for Raith here as it looks like he'll be coming on soon.
GOAL! McCowan adds a third
Luke McCowan adds a third within two minutes of the restart!
Yang pulls it back from the left and the midfielder is at the right place at the right time to direct it goalward and put this one, realistically, out of sight.
Damage limitation for Raith now, you would think.
RESTART! Celtic 2 Raith 0
Ths visitors kick us off as they look for one of the ultimate Scottish Cup comebacks!
HT! Celtic 2 Raith 0
A clinical first half from Daizen Maeda is the difference here as Celtic are just too good for their Championship opponents.
One more in the second half and it's 50 Celtic goals for the Japan star – will he get it?
Find out with us very soon!
GOAL! Maeda makes it two
That one's going to count!
No one's stopping Daizen Maeda today. Scintillating from Celtic, back to front in the blink of an eye, Yang picks out Maeda, and it's 2-0.
A long second half for Raith awaits!
GOALLLNNNOOOO!
Maeda thinks he has his second, but nope, offside.
Anthony Ralston picks him out at the back post but it did look like he strayed half a yard off.
Halon slams the door in Kuhn's face
Celtic advance menacingly but the big centre-half is having none of it and sends it out for a throw.
The Hoops want a second before half-time.
A sore one for Bernardo
And it looks like it's game over for the Portuguese midfielder.
An ankle injury it looks like, and Reo Hatate is called back from his warmup.
Yep, on comes the Japanese star as Bernardo is applauded off.
The big moment
And it was a great finish from Maeda to put the Hoops in front.
Rovers might have feared a messy evening at that point but there's not been too much goalmouth action since.
An outcome Barry Robson will probably take as we enter the final 10 of the first half.
Pass, pass, pass....
...pass, pass, pass.
Did I mention 'pass'?
It's death by a thousand cuts for Raith Rovers here. Celtic always have a short passing option available and they're using them to take the sting out of the game which the visitors briefly offered.
Mullen denied by Sinisalo
Jamie Gullan plays a clever ball over the top to Joshua Mullin down the Rovers right and the winger has a clear sight of goal.
He attempts to lob the advancing Sinisalo but the keeper is equal to it with a strong stop, his first real action in a Celtic shirt.
It might have been going wide anyway but this is the first sign of a real spell from Raith.
Raith advance menacingly
A first real spell of Raith getting their foot on the ball and there's a sign danger-man Dylan Easton could do some damage here.
He combines nicely with Ross Matthews down the Raith left, but Celtic tidy it up and counter through Maeda.
Nothing comes from it and it stays at 1-0.
Bernardo taken out
Robust tackles from Scott Brown in the midfield typically get a cheer around these parts, but not when the Raith Rovers captain takes out Paulo Bernardo.
The Celtic hero's namesake leaves a bit in on the Portuguese midfielder and there's a stern look in his direction from whistler Chris Graham.
But for now a free-kick is all it gets.
Gullan suffers injury scare
Barry Robson has a change ready as his main striker Jamie Gullan takes a sore one.
But for now it looks like he's giving the frontman every chance to play on.
He's not moving properly but is going to troop on and try to run it off.
Utter dominance
Have Raith been out of their own half yet?
There's a long evening in store for Barry Robson's team at this rate...
GOAL! Maeda opens the scoring
Well that took long!
Not even six minutes on the clock and Daizen Maeda has opened the scoring!
A lovely left-footed effort from the player of the season contender who strokes it into the bottom corner with his left foot!
Kuhn goes close from range
But his whistling left-footed effort is over the bar.
It likely wouldn't have counted anyway as the referee blows for a foul on Euan Murray.
