The Nets' sponsorship deal with American Express was officially announced without much fanfare Monday, no mention of the Knicks' former contract with the credit card company. But make no mistake, this is a big deal, especially when combined with the Nets' seven figure advertising campaign that also began Monday.

As Alex Raskin writes for HoopsWorld, "It’s going to take more than a sponsor revolt for the Brooklyn Nets to declare victory in their turf war with the New York Knicks. But if we had to pinpoint the day the Nets struck their first major blow, Monday would be a good candidate." The reason is that American Express had been everywhere at Madison Square Garden.

Similarly, the Nets' highly personalized ads are aimed to make the team's "Core Four" as familiar as the Knicks' all-Stars. The two teams may be publicly saying all the right things about how competition is healthy and will help both teams, but not far below the surface, there's real animosity.

• NBA PM: Nets Invading Knicks' Turf - Alex Raskin - HoopsWorld
• NETS: AmEx, Barclays Center, and Nets Announce Alliance - Brooklyn Nets
• Brooklyn Nets introducing borough to team's 'Core Four' - Mike Mazzeo - ESPN New York
• Nets launch B'klyn All-Star marketing campaign - Tim Bontemps - New York Post
  
• Nets Bid Brooklyn "Hello" In Series Of Billboards (Video) - NY1
  
• Nets Get Personal For Next Phase Of 'Hello Brooklyn' Campaign - WFAN
• Brooklyn Nets Debut New Phase of 'Hello Brooklyn' Campaign - Adelle Platon - Vibe