It seems like the Spurs' players and coaches tried to go into that game pretending it was just another regular season game. You can tell the media that and you can tell the fans that, but the players know it isn't true.
The intensity that the Heat and Thunder showed against each other is a result of two teams recognizing the psychological importance of certain "statement" games. The Lakers came out wanting to prove something. Mike Brown wanted to prove he isn't re ed and/or worthless, and every player on his team wanted to prove they can dominate the Spurs when they "turn it on", especially in San Antonio and especially without Kobe. That's the mentality they brought last night.
In the meantime, Pop pretended his current player rotation would suffice, and Duncan, Parker and Ginobili walked out onto the court expecting "just another regular season game." Stephen Jackson and Danny Green knew differently and played like this game actually meant something. They weren't scared or intimidated because they recognize they have a lot to prove.
I think the effort was there from Tiago, and overall I don't think he played poorly. Lately he's been playing like he's up to the challenge of earning every possible minute out of the 5-bigman rotation. In reality, he actually earned those minutes a long time ago, so I can only imagine he's frustrated with his current role.