Electing to bat, Rajasthan posted a challenging 177 for six with all their top-order batsmen, barring Ajinkya Rahane [ Images ], contributing and then restricted Kings XI Punjab to 134 for eight at the PCA Stadium on which the ball came nicely on to the bat.
Chasing 178 for a win, Punjab were in the game only for a brief while when opener Shaun Marsh [ Images ] (34) was going great guns with some lusty hits but once he was out in the ninth over it was all over for the home side as they lost wickets at regular intervals.
The match was as good as over by the 15th over when Punjab were 97 for five and the asking rate had shot up 16 an over.
With the win, Rajasthan jumped to the fifth spot in the league table with 10 points from 11 matches while Kings XI Punjab occupy the sixth place with same 10 points from 11 matches but one rung down on lesser net run rate.
Kings XI were on the back foot early with opener Mandeep Singh falling to Watson in the second over as his pull shot went straight to mid-on fielder Siddarth Trivedi.
Marsh then milked Ankeet Chavan 18 runs in the seventh over as he hit the bowler for three fours and a six to give the home side hope for a win.
But, just after that big over came the blow as captain David Hussey [ Images ] perished while going for a pull shot only to find a running Brad Hodge [ Images ] taking a good catch as Punjab were reduced to 55 for three in the eighth over.
The home side slumped to further trouble as Marsh followed his captain to the dressing room in the next over as he was clean bowled by Botha.
By the halfway mark, Kings XI Punjab were in dire straits at 65 for four and the asking rate shot past 11 an over.
Azhar Mahmood (24) and debutant Gurkeerat Singh (23) tried hard for boundaries but to no avail. The former perished while trying for big shots, castled by a slow delivery from Binny as KXIP were reduced to 97 for five at the end of 15th over, needing 81 runs for a win.
Rajasthan could have shut out the match sooner rather than later but for their butter-fingered fielders as the visitors dropped at least three catches.
But, the home side could not capitalise on them. Rather, their run chase was all over as the asking rate shot past 16 an over by the end of the 15th over and with half of their batsmen gone.
By the end of the 17th over, the asking rate had gone past 20 an over as Gurkeerat, Piyush Chawla [ Images ] (5) and Rayan Harris (3) could not give a fight as the home side fell short by a whopping 43 runs.
Earlier, Rajasthan scored 177 for six with contributions from captain Rahul Dravid [ Images ] (46), Watson (36), Ashok Menaria (34) and Brad Hodge (36).
For Punjab, Australian pacer Ryan Harris scalped four wickets for 34 runs while leg-spinner Piyush Chawla took two wickets for 38. All the Punjab bowlers went for runs but they came back strongly in the second part of the innings to restrict Rajasthan to 177 for six.
Watson was the most aggressive of the Rajasthan batsman as he hit four fours and two sixes while Dravid, who hit eight four in his 39-ball innings, held one end initially before he was out in the 14th over.
After Watson was out in the eighth over, Maneria carried on the tempo with some lusty hits. He was though lucky as he was dropped near the boundary by Mandeep Singh. He was eventually out off the bowling of Chawla in the 16th over.
Hodge then took the score past 175 with some big hits, including a six each off Harris and Azhar Mahmood. Harris, however, had the last laugh as he claimed Hodge's wicket in the final over.
Rajasthan lost in-form opener Rahane in the second over. After hitting a boundary off Harris, Rahane tried to cut a ball that was moving away from him and with wicketkeeper Nitin Saini completed the catch.
However, the visitors quickly put the tournament's top run getter's loss behind them as Watson cut loose with Dravid also in great touch.
When Harris was back to bowl his second over, Dravid hit three consecutive boundaries of him followed by two hits to the fence of Praveen Kumar [ Images ] and another one from Watson.
Both batsmen hit some lusty shots of medium pacer Praveen Kumar, who gave away just eight runs in the previous match.
Medium pacer Parvinder Awana also came under heavy fire from Watson who hit him two boundaries and a six when the bowler was brought in the sixth over in which he gave away 19 runs.
Dravid and Watson weaved a 69-run partnership for the second wicket before the Australian fell to Chawla in the eighth with Harris making a valiant diving effort at long off to take the catch.