When it comes to sport, momentum can change faster than a Lady Gaga back-up dancer between sets.
In team sports especially, the longer you can hold on to and build on that momentum the better your chances of winning.
The Bay of Plenty Steamers learnt that the hard way in their opening Mitre 10 Cup game on Sunday.
They travelled to Northland to take on the Taniwha and dominated territory and possession in the first half. They had all the momentum and led 23-7 at halftime - they were flying.
In the second half, from the kickoff, the Steamers produced an error inside their own 22. It caused an instant shift in momentum which, to their credit, Northland pounced on and maintained. They never looked back and romped home for a 28-23 comeback victory.