Both strikers found the back of the net in a breathless encounter which saw Youssouf Mulumbu give the home side the lead and both teams miss numerous chances
Defoe smashed a low shot past Ben Foster to give his side a 3-1 victory after Adebayor's first half goal from the rebound of his missed penalty had pulled his side level.
The on-loan Manchester City forward then tapped in late on to make the score look even better but the damage had already been done.
West Brom had taken the lead through Youssouf Mulumbu early on and will feel hard done by not to have had at least one penalty throughout this absorbing contest.
West Brom had gone into the match with an unchanged line-up from the 2-0 win over Bolton Wanderers, with Paul Scharner making the bench alongside Peter Odemwingie who had caused headlines after he had tweeted a picture of his bruised leg having appeared to be criticised by manager Roy Hodgson during the week for a failure to get himself fit.
Harry Redknapp had a few more problems with key duo Luka Modric (illness) and Rafael van der Vaart (hamstring) missing from the squad, but he was able to bring in Sandro and Defoe to the starting XI.
Both these teams have scored five times in the opening 15 minutes of matches this season and West Brom soon added to their total. Gera did well on the right to shield the ball from Benoit Assou-Ekotto on the slide and once he returned to his feet, he was able to feed Reid whose first-time cross split Ledley King and Younes Kaboul, only to find Mulumbu who flicked it into the net past Brad Friedel.
The home fans great mood was soon dampened as Gera was forced off after twisting his ankle on the pitch, allowing Simon Cox a rare chance to play most of a match.
Soon after that change Spurs equalised as West Brom conceded their third penalty in as many home matches. A lovely Adebayor back-heel set Lennon into the area and he appeared to be tripped by Nicky Shorey in a tangle of legs although it was hard to tell how much contact there was.
The spot-kick was taken by Adebayor, but was weak and easily saved by Foster diving to his right, but the Togolese got to the rebound first and bundled it home for his third goal in a week.
The last 15 minutes of the half then saw a large amount of drama as the home fans believed they had two shouts for a penalty and that Sandro should have been sent off.
Moments later, King tangled with Shane Long in the area and the home fans again appealed for a penalty but nothing was given.
In between all of this, the Baggies faithful thought they had taken the lead again when the linesman flagged as Friedel looked to have taken the ball perilously close to his goal-line, but their cheers were soon cut short when they realised a free-kick had been given to the Spurs goalkeeper for a nudge on him by Gareth McAuley.
After the interval the visitors were the first to threaten as Parker thread a pass through the legs of Olsson but Adebayor’s shot was well saved by Foster at his near-post.
Defoe deadly | England forward competed comeback with a powerful finish
The Baggies then should have taken the lead but after great work down the right by James Morrison, Cox could only head straight at Friedel from close range.
The tempo of the game was electric and back came Spurs. Defoe raced past the home defence, but Olsson did well to knock him off his stride and after being forced wide, his shot was cleared by the covering Reid.
In the space of a couple of minutes Morrison nearly broke through the Spurs defence only for the side playing in purple to get to the other end of the pitch, but after Defoe had flicked a ball into the box in the direction of Adebayor, the striker’s casual finish was parried by an on-rushing Foster.
However, the third goal finally came and it was the impressive Defoe who got it. Receiving the ball in the West Brom half, he was left in acres of space to run at Olsson, before creating a yard of space and smashing the ball low into the corner.
Adebayor then missed another sitter, before tapping in Bale's centre to give his side another goal, although this only came after Odemwingie had headed over for the home side who have not scored in the last 10 minutes at all this season.