Sofien Moussa gave Dundee a big derby boost by scoring a hat-trick against Cowdenbeath at Central Park.
The Tunisian striker had bagged the treble by half-time, banging in goals on 17, 23 and 38 minutes – the pick of the bunch an overhead kick for the second.
Moussa had plenty of other chances – particularly before the break – but Cowden were spared further punishment.
Job done, the 29-year-old walked off to be replaced by substitute Marcus Haber just after the hour and enjoyed the applause delivered by the travelling supporters as he left the Central Park pitch.
Now Moussa will look forward to leading the line against Dundee United at Dens on Sunday in the game that will decide which of the city teams finishes top of Betfred Cup Group C.
The Dark Blues, watched from the stand by Tangerines boss Ray McKinnon, made four changes to the side that started that unconvincing cup win over Buckie Thistle at Dens on Saturday.
Out went Jack Hendry, Lewis Spence, Randy Wolters and the injured Faissal El Bakhtaoui, while there were places in the line-up for skipper Darren O’Dea, Scott Allan, Glen Kamara and Mark O’Hara.
The visitors looked in control of the game from early on and an Allan freekick to the near post had to be saved by home goalie Joe McGovern after just four minutes.
With 10 minutes on the clock, Dundee right-back Cammy Kerr was confident enough to try a strike from 25 yards but McGovern made the stop.
It looked just a matter of time before the Dens men took the lead and the opening goal duly arrived on 17 minutes.
The scorer was Moussa, slamming the ball past McGovern after being found by an Allan cross.
The big Tunisian was at it again just six minutes later and this one was an absolute cracker.
Moussa was alert and agile as he executed an overhead kick from close range to make it 2-0 to the Dark Blues.
O’Dea saw his decent header saved by McGovern just a minute later as Neil McCann’s men piled on the pressure but Cowden finally had a go at the other end, with Kyle Miller spinning and shooting only for O’Hara to block.
Moussa could have had his hat-trick on 29 minutes but for McGovern coming out to meet him then the same player sent a header wide three minutes later.
Cowden had a claim for a penalty ignored by referee Euan Anderson when David Syme went down inside the box but Dundee simply went up the other end and scored again.
It was that man Moussa with his treble on 38 minutes, nodding home after good set-up work by both Deacon and Paul McGowan.
The big man was clearly enjoying himself and it could have been four a couple of minutes before the break had his header gone under the bar – as it should have done – and not over the woodwork.
Three minutes after the interval, Deacon raced down the right then squared the ball to McGowan, whose curling shot was well saved by McGovern.
A combination of an improved home performance and the visitors having the match sewn up meant second half wasn’t all one-way traffic but Deacon had a chance on the hour when he chipped the advancing McGovern but the ball landed on the roof of the net.
A terrific saving tackle from Cowden defender Scott Rumsby stopped Allan in his tracks and that was the Dundee midfielder’s last piece of action as both he and man-of-the-night Moussa were replaced by Wolters and Haber.
The visitors then made their final change, with James Vincent coming on for Kamara on 70 minutes.
Kerr let in Cowden’s Harvey Swann on 76 minutes thanks to a dodgy header and when the cross came over it needed Kevin Holt to clear the danger.
Shaun Rutherford was booked for chopping down a rampaging O’Hara – the first yellow card of the night – before Matthew McInally came on for the hosts, replacing Cameron Muirhead on 82 minutes.
Dundee comfortably saw out the remainder of the match and now sit on nine points in Group C – the same as United, who have the better goal difference.
With the penalty shootout giving out a bonus point at Dens, though, there will have to be group winner at the end of the derby.
Cowdenbeath: McGovern, Pyper, Rutherford, Mullen, Rumsby, Syme, Muirhead (McInally 82), Buchanan, Morris, Miller, Swann. Subs not used: Penman, Ovenstone, Thomson, Leslie, Turnbull, Henderson.
Dundee: Bain, Kerr, Holt, O’Dea, Kamara (Vincent 70), Moussa (Haber 63), Allan (Wolters 63), O’Hara, McGowan, Deacon, Waddell. Subs not used: Parish, Hateley, Hendry, Spence.
Referee: Euan Anderson.