Steve Smith has failed again with the bat and was then forced to watch his star-laden Rajasthan Royals' side slump to another defeat in the IPL after a disappointing run chase against table-topping Delhi Capitals.

Smith was caught and bowled for just one off four balls by Ravi Ashwin as the Royals chased 162 to win before the former Australian captain then again saw his batting line-up capitulate to 8-148, losing by 13 runs.

It continued the former Australian captain's individual slump as he has now failed to get into double figures in five of his last six innings, seemingly struggling to come to terms with the slow paced pitches.

Those last half-dozen innings, after he began the campaign with a couple of bright half-centuries, have seen him score 3, 5, 6, 24, 5 and now one.

The captain's lack of runs have come hand in hand with his team's slide to one from bottom of the league, with the Royals having won just three of their eight matches and just one of their last six.

"We are not in a great position, are we? We have got to quickly move on and come back with a big game in three days time," Smith conceded.

"On a slow wicket it is difficult to make up runs in the end. Guys kept getting in and kept getting out, and not making 60-odd to see us through."

Delhi were thankful to the pace of Anrich Nortje and Kagiso Rabada to seal Wednesday's win.

Nortje (2-33) claimed the key wickets of Robin Uthappa (32) and Jos Buttler (22) and together with Rabada (1-28) tied down hard-hitting Rahul Tewatia in the end to restrict Rajasthan.

Delhi had earlier scored 161-7 on the back of Shikhar Dhawan's second successive half-century as the left-handed opener scored 57 and captain Shreyas Iyer added 53.

Australians Marcus Stonis (18) and Alex Carey (14) made useful late contributions.

In a game dominated by pace bowlers, Jofra Archer was again outstanding, having clean bowled Prithvi Shaw off the first ball of the match and finished with figures of 3-19.

English duo Buttler and the returning Ben Stokes (41) provided a rollicking start for Rajasthan by smashing 37 runs in the first three overs.

Stokes, playing in only his second game this season, hit six fours before he was outdone by seamer Tushar Deshpande's slow delivery and holed out in the deep midway through the Rajasthan run-chase.

Delhi now sit on top of the table with 12 points after winning six of their eight games.