Big players return for a big game.

Keanu Baccus is back in the St Mirren starting line-up after being off on international duty with Australia in the Asian Cup.

James Bolton was sent off in the midweek win against Dundee so he's out today as is James Scott and of Kwon Hyeok-kyu is unable to play against his parent club. Charles Dunne and Lewis Jamieson are in.

Brendan Rodgers has switched things up with a 4-2-2 formation, and the big news is Kyogo Furuhashi is back after starting on the bench in the win against Hibs. He partners birthday boy Adam Idah up top.

Tony Ralston is in for the injured Alistair Johnston and Luis Palma tags out Nicholas Kuhn, while Paulo Bernardo also drops to the bench.

Image source, SNS

Quite the stat: Brendan Rodgers has never lost a Scottish Cup game.

Does that continue or end today?

Image source, SNS

From wild scenes at Cappielow and bedlam at Firhill, to a clinical double from Bojan Miovski...

Catch up with the best of the weekend action so far by bashing those play buttons below.

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Celtic are getting by, but they've looked a bit out of sorts recently.

A trip to Paisley wasn't the kindest of draws, given St Mirren took four points off the champions last season.

But Stephen Robinson's side took three hidings in between and have lost both league meetings this time round.

Celtic have been unconvincing since the campaign resumed, enduring uncharacteristic struggles in front of goal.

St Mirren will have noted how Hibs and Aberdeen gave the Scottish Cup holders a fright in the past week when having a go, but that's easier said than done.

Image source, SNS

Celtic manager Brendan Rodgers tells BBC Sportsound: "This is a tough game for us, and a big one. We want to get through and to do that we'll need to give 100% in everything we do. This is probably the toughest team we could have faced in this moment.

"Over the course of the season, our performances have been a little inconsistent, so the aim is to continue to work on that, but in a cup game it is just all about getting through.

"If we're a team that aren't running, we're lost, so we need to run and break lines and get in behind. When we do that, we look a really good side.

"We will press in our normal structure, as we do in a 4-3-3, so it's just a slight adaptation [going to a 4-4-2]."

BBC Radio Scotland

We've been treated with a bumper Sportsound today.

There will be over six hours of radio coverage on BBC Radio Scotland, starting from 13:30 GMT.

The gang will provide live commentary from Paisley and Airdrie.

Dundee: Carson, McGhee, Sylla, Shaughnessy, Donnelly, Beck, Cameron, Tiffoney, McCowan, Bakayoko, Robinson.

Substitutes: Sharp, Dodgson, Astley, Lamie, Ashcroft, Mulligan, Robertson, Mellon, Costelloe.

St Johnstone: Mitov, Olufunwa, K Smith, Considine, Gordon, Robinson, M Smith, Kjeltens, Carey, Kimpioka, Sidibeh.

Substitutes: Richards, Gallacher, McGowan, Kane, Clark, Jaiyesimi, Kucheriavyi, Sprangler, C Smith.

St Mirren: Hemming, Fraser, Gogic, Dunne, Bwomono, Baccus, Boyd-Munce, Tanser, Kiltie, Mandron, Jamieson.

Substitutes: Urminsky, Taylor, Brown, Flynn, Mooney, Penman, Olusanya, Scott, Ayunga.

Celtic: Hart, Ralston, Welsh, Scales, Bernabei, McGregor, O'Riley, Palma, Maeda, Idah, Kyogo.

Substitutes: Bain, Kuhn, Yang, Nawrocki, Oh, Iwata, Bernardo, Vata, Kelly.

Line-ups, anyone?

Scottish Cup:

• St Mirren v Celtic (14:00)
• Airdrieonians v Hearts (17:00)

Scottish Premiership:

• Dundee v St Johnstone (14:00)

Image source, SNS

Three games, two competitions and a cup draw.

As far as Sundays go, I reckon we're in for a pretty decent one.

Scottish Cup last-16 weekend comes to an end with two belting ties, plus we have a top-flight Tayside derby at Dens Park.

Bliss.