Chasing 215 for victory against Punjab, Hyderabad reached the target with five balls to spare at their home
The south coast side went into the game second bottom in the league, having lost their first four fixtures and scored only once.
Their miserable run looked like it might continue as, after a goalless first half at the Vitality Stadium, the visitors took a surprise lead 10 minutes after the break when Solly March headed in his first Premier League goal from Pascal Gross's cross.
Chris Hughton's side were ahead for 12 minutes before Bournemouth's Jordon Ibe changed the game. The influential former Liverpool attacker found South African midfielder Andrew Surman in the middle of the box, who finished in the far left corner of the Brighton goal.
Ibe turned provider again little more than five minutes later, showing good control outside the area to hold onto the ball and play it through to veteran Defoe.
The 34-year-old did not need to take a touch as he span quickly and struck the ball low past goalkeeper Mathew Ryan to score his first goal in a Bournemouth shirt since he lined up alongside his now manager 16 years ago.
"He's an unbelievable professional. He sets the example. He wants to train every day, he doesn't want to be treated as a special case, he really wants to muck in and be one of the boys... He's got the finishing ability to score lots of goals for us," Howe told Sky Sports.
After securing their first ever Premier League win last week over West Bromwich Albion, Brighton found they relaxed too much after going in front against the run of play.
"(I am) incredibly disappointed. They have a lot of quality and move the ball well but we handled it well for a lot of the game," Hughton told reporters.
"It was two poor goals we conceded. We never looked like conceding before then. I thought it was a really good period for us just before we scored."
The two sides meet again at the same venue on Tuesday in the third round of the League Cup.
Following that, Bournemouth travel to Everton in the league next weekend while 14th-placed Brighton host Newcastle United.
Chasing 215 for victory against Punjab, Hyderabad reached the target with five balls to spare at their home
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