Newly-promoted UCD produced a remarkable 3-1 win over reigning national champions Three Rock Rovers to kick-start the men's EY Hockey League in spectacular fashion.
The students scraped their way to promotion in the spring via a shoot-out but, after a summer of quality recruitment, look to be contenders for the top half of the table on this showing.
Conor Empey is one of nine new arrivals and he broke the deadlock against his old club inside the first 10 minutes. Ben Walker levelled but second-half goals from Jazze Henry and Guy Sarratt - the league's top scorer last year when with Monkstown - earned UCD the spoils with a controlled performance.
The other promoted side, Corinthian, came within a couple of minutes of recording a win, too, but they were denied by Ryan Burgess's 67th-minute goal at a well-attended Whitechurch Park, Annadale nabbing the 2-2 draw.
Elsewhere, Lisnagarvey hammered Pembroke - who were expected to be challengers this term - 6-0 to show they mean serious business with James Lorimer firing a hat-trick.
Stephen Brownlow struck with the last touch of the game for Glenanne to beat YMCA 3-2. Monkstown and Banbridge shared the spoils in another 2-2 outcome.
In Munster Division One, meanwhile, the province's biggest derby saw Cork C of I thump champs Harlequins 6-2 on opening day, a big hint that they are likely to be the team to beat following their shock relegation last term.