Rajasthan Royals rode on another sizzling innings from Jos Buttler to edge past Kolkata Knight Riders by seven runs runs for their fourth win of the Indian Premier League on Monday. Buttler has hit a purple patch this season, having already reached three figures earlier in the tournament against Mumbai Indians. Against Kolkata at the Brabourne Stadium in Mumbai, Buttler smashed 103 off 61 balls with nine fours and five sixes to help Rajasthan pile up 217-5. Kolkata chased brilliantly before getting dismissed for 210 in the final over. Buttler entered the match with a century and two fifties in his last four outings and once he got going, the England wicketkeeper batsman was always going to make it count. Buttler added 97 with Devdutt Padikkal, who only reached 24 when he was dismissed by Sunil Narine in the 10th over. Narine turned out to be the best bowler for Kolkata, finishing with outstanding figures of 2-21 as the rest of the bowlers were carted around the park. For fast bowler Pat Cummins (1-50), it was the fourth straight occasion where he went for more than 10 an over. Rajasthan's innings threatened to derail towards the end but Shimron Hetmyer hit two sixes and a four off Andre Russell to finish with a flourish. Kolkata's innings started in the most disastrous fashion possible - a first-ball run-out of Narine without facing a ball. Aaron Finch (58 off 28 balls) and Shreyas Iyer (85) took the attack to the opposition but the challenge lost steam when Prasidh Krishna had the Australia captain caught at point. The contest looked like it was over when Yuzvendra Chahal trapped Iyer lbw in the 17th over. Chahal capped a memorable night by picking up four wickets in that over, completing a hat-trick for figures of 5-40. But a late blitz by Umesh Yadav (21 off 9) raised Kolkata's hopes before he was the last man out.