Alright, something about reality:
The best man doesn't always win.
Actual battles aren't like Dragon Ball Z where you summon your power and shoot it at the other person and whoever's power is bigger wins.
People get caught off guard, people make mistakes, miscommunications and bad decisions occur.
There are a myriad of reasons dooku could have neutralized Obi-Wan in their second battle without Obi-wan being vastly inferior to Dooku.
Perhaps Obi-Wan, being unadept at space combat, was mentally drained from their earlier space intrusion and was thus not at his prime during the battle.
Perhaps Obi-Wan expected Anakin to make a move there that did not occur, which put him off guard and allowed Dooku to take advantage of their miscommunication.
Perhaps Obi-Wan was overconfident in the situation since it was two on one and was not being as precatious as he should have been.
I could keep perhapsing on and on. Obviously it happened so Anakin could be alone with palps and Dooku for the plot, but that doesn't mean the situation occuring was invalid. Sometimes the better man loses.