Watson set the tone early on when he launched an attack against Sandeep Sharma, hitting the bowler for a four in his first over followed by two sixes in his next. Buttler was adjudged the Player of the Match for his fourth consecutive half century in the tournament.
Rajasthan required 28 runs from the last twelve balls but CSK couldn't defend those runs as David Willey leaked 16 from the penultimate over and Dwayne Bravo couldn't contain in-form Jos Buttler from scoring 12 from the last over.
The next stop: Both teams face tantalising matches in their next outing, Chennai hosting ladder-leaders Sunrisers Hyderabad on Sunday night desperate not to drop a second-straight game. The MS Dhoni-led side scored a comfortable eight-wicket win over Sunrisers Hyderabad to register their 8th win of the season, and with 16 points they have nearly secured their place in the top-4.
RR got off to a flying start, thanks largely to Buttler, who has shown his true worth since being promoted to open the innings. That back of the length was a hard one to hit.
The Sunrisers Hyderabad opening batsman returned to form with a stroke-filled 92 not out in a successful run chase against Delhi Daredevils, and will be an important member of the SRH side when they take on CSK.
But the veteran off-spinner had his revenge in the very next ball when the Englishman went for another big hit but the incoming delivery managed to find the gap between bat and pad to disturb the stumps. If Chennai wins this match, then qualify for the playoffs.
Sanju Samson (21) was run-out after a frightful mix-up while debutant Prashant Chopra (8) hit a couple of boundaries before failing to pick a slower from Shardul.
Stturat Binny also failed to last long as Chennai seemed destined for another win. However it was the wicket of Williamson, who had just completed his 7th fifty, highest for any player this season, off the next ball for 51 off 39 balls that really hurt SRH's aspirations.
In the 43 match (CSK vs RR) of IPL 2018, a combined batting effort by Suresh Raina, skipper MS Dhoni and opener Shane Watson helped Chennai Super Kings post a fighting total of 176 against Rajasthan Royals.
After winning the toss, Chennai posted 176-4 from their 20 overs, with Indian global Suresh Raina top-scoring with 52 off 35. Watson was Archer's second dismissal.
It was left to Mahendra Singh Dhoni (33 off 23 balls) again.
WICKET! Pandey's awful run continues.