Lawrence Shankland laid a marker with two penalties in the space of three minutes as the Hearts captain gave new boss Derek McInnes a winning start with a hard-fought Premier Sports Cup victory over Neil Lennon's Dunfermline.
The striker ended months of contract speculation by signing a new three-year contract a week ago and showed his intent with two clinical finishes to help his side take control of the clash with the Championship Pars.
With the match tied at 1-1 heading into the final quarter of an hour, a penalty shoot-out appeared to be looming until Shankland turned the tide.
Despite protesting his innocence and in the absence of VAR, Deniz Mehmet was adjudged to have fouled Alan Forrest in the box and Shankland sent the Pars keeper the wrong way from the spot.
Barely three minutes later, the skipper stepped up again and made no mistake after substitute Elton Kabanga was dragged to the ground.
The Jambos had raced ahead when James Wilson finished from close range with just three minutes on the clock and looked to be in control, but Lennon's side capitalised on a slack Beni Baningime pass and John Cooper calmly finished.
Having restored his side's dominance, Shankland left the field to a rousing ovation with minutes to go as he was replaced by Stephen Kingsley, and the substitute wrapped up victory with a fine finish in stoppage time.
Steven Pressley was given a rude welcome on his competitive return to Scottish football as his Dundee side slumped to a shock loss as the group stage got into full swing.
The new Dens Park boss saw his Premiership outfit slip to a 1-0 home defeat against second-tier Airdrieonians as Chris Mochrie grabbed the decisive goal midway through the first half, turning his marker and firing past Trevor Carson in the Dundee goal after being set up by Diamonds' player-manager Rhys McCabe.
Dundee came closest to levelling after the break when Billy Koumetio's header was cleared off the line while skipper Simon Murray couldn't find the target with a left-foot shot. In the other Group C tie, Luke Rankin's goal in the second minute was enough to secure victory for Alloa at Bonnyrigg Rose.
Pressley believes the defeat revealed the extent of work that lies ahead of the Tayside club.
He said: 'We wanted to give the supporters some real hope but the reality was we weren't good enough.
'We were out of sync with many of the things that we've worked towards, but it'll take time.
'I know people don't like to hear that, but it will take time.
'We've been on the grass 19 times together and we have to keep working - we have to keep believing.
'But the one thing that today I think emphasised was that we have a lot, a lot of work ahead of us.'
It was also a bad day for St Mirren boss Stephen Robinson - whose team finished sixth in the top flight last season - as the Buddies were beaten 5-3 on penalties by Championship side Arbroath at Gayfield after a goalless 90 minutes.
Down to 10 men after Mark O'Hara's second booking on 88 minutes, Robinson's men saw Red Lichties goalkeeper Aidan McAdams deny Fraser Taylor in the shoot-out before Calum Gallagher netted the winning spot-kick to earn two points for the hosts, with the Paisley side taking one.
A clearly upset Robinson said: 'I'm in a little bit of shock.
'The performance of maybe 13 of them is something I've not seen all pre-season. We've had a fantastic pre-season.
'I didn't recognise some of the decision-making, some of the passing, some of the simple things we've continually done through the pre-season.
'We decided as a collective not to do that and got exactly what we deserved.
'Out of the team that started, Peter Urminsky and Marcus Fraser arguably are the only people that come out with any kind of credit or I at least recognised their performances.
'I didn't see that coming I have to be honest, I did not see that coming at all.
'We're extremely disappointed. There has to be a reaction. We are and will be better than that.'
Penalties also decided the other Group D clash, Forfar Athletic winning 4-2 against Annan Athletic after being tied at 1-1 in normal time.
Motherwell's new manager, Dane Jens Berthel Askou, was without injured Lennon Miller as the Steelmen were held by Clyde at New Douglas Park before taking the penalty shoot-out bonus point. James Hilton put the Bully Wee in front with an early strike from distance but Tawanda Maswanhise headed Well level soon after and put them ahead early in the second half before Liam Scullion nodded in to make the tie all-square again.
The Fir Park side triumphed 5-4 on penalties, with Calum Ward's save from Logan Dunachie's attempt proving decisive. Midfielder Miller, the subject of intense transfer speculation, is expected to be out for 10 days after a knock in a closed door game against Carlisle. In the other Group G clash, Morton won 4-2 at Peterhead.
Askou claimed there was a 'good amount of learning' to take from the clash with Clyde.
He said: 'Yeah, you can always look at it from two perspectives and say, "yeah, it's not good enough, we didn't win - we should have won".
'But we also knew that it could be really, really difficult and we weren't sharp enough in the moment.
'We had a big chance at the end where we could have closed the game down.
'But that's football. I'm sure that this game will not define the journey we are (on) with this club.
'But it was a good learning step in terms of dealing with a little bit of frustration, irritation, that it wasn't as fluent as we wanted to be and then how to deal with that and keep the body language positive and so in terms of that, there's a good amount of learning in it.'
Kilmarnock handed Stuart Kettlewell a comfortable win in his first competitive game in charge as they eased past Highland League Brora Rangers. Ben Brannan broke the deadlock from inside the penalty area just before half-time, with Dutchman Djenairo Daniels opening his account for his new club with Killie's second with 10 minutes to play.
David Martindale's Livingston, who are back in the Premiership this season, edged past East Fife in the other Group H match. Robbie Muirhead and Macaulay Tait struck either side of half-time before Pat Slattery reduced the arrears shortly after, but the promotion play-off winners held on for victory at Bayview Stadium, with a visit to Rugby Park next up on Wednesday.
Championship winners Falkirk swept Highland League Brechin City aside 7-0, with Dylan Tait notching a hat-trick for John Glynn's Bairns side. New signing Brian Graham set up Scott Arfield to open the scoring, Arfield getting a second from the spot after Tait had grabbed Falkirk's second. Alfie Agyeman made it 3-0 to the visitors, with Tait completing his hat-trick late in the second-half and Ross MacIver completing the rout in added time.
In the other Group A tie, League 2 Spartans pulled off a surprise 2-1 win over Championship Queen's Park.
Relegated Ross County slipped up at League 2 Stranraer, as Don Cowie's men lost in a penalty shoot-out. Ronan Hale put the Staggies in front just before the interval but Tommy Sharp levelled from close range with 14 minutes left.
Home keeper Josh Lane - signed on loan from Hamilton just hours before kick-off - saved three times in the shoot-out with Lewis Hunter netting the decisive kick to give the hosts the bonus point in their Group B clash.
Simo Valakari's St Johnstone recovered from the loss of an early goal to ease past league new boys East Kilbride at K Park. John Robertson's stunning free-kick had Kilby ahead but Jamie Gullan replied with an equally impressive set-piece goal after the interval and an Adama Sidibeh breakaway strike and Makenzie Kirk close-range effort wrapped up victory.
In the other Group F encounter, Championship Raith Rovers romped to a 5-1 victory at League 2 Elgin City. Dylan Easton's penalty double and goals from Jai Rowe, Lewis Vaughan and Josh Mullin ensured Barry Robson's side were never in danger, with Jack Murray's effort a consolation for City.
Two goals in seven second-half minutes secured victory for John Rankin's Hamilton side at Stirling Albion. Connor Smith found the top corner from distance before a Kyle MacDonald header wrapped up victory in the Group E clash.