Chennai, Apr 22 (IANS): Mumbai Indians' strength -- the power-packed middle-order -- has not done well in this year's Indian Premier League (IPL) so far, leaving the defending champions with below-par totals.

In two of the four matches MI have won, they have survived thanks to their bowling as well as some poor batting from their opponents.

However, in the two games they have lost, it was their power-hitters' failure that stood out.

Despite a strong batting line-up, they are yet to reach 160 even once.

Neither of the two Pandya brothers have done well in the tournament so far and Kieron Pollard has clicked in only one game with the bat which MI won against SunRisers Hyderabad thanks to the West Indian's batting.

MI pace bowler Trent Boult acknowledged that his team's middle-order batting has failed but said that the bowlers will have to be better-prepared.

"Not pleased with the way things have gone so far. They are hungry and desperate after the performance in the last game. Not the ideal start, but obviously would like a few more runs on the board," said Boult while speaking to the media on Thursday.

"But that (bowlers rising to the occasion) is one of the strengths of the side… bowlers will have to be mentally prepared," added the left-arm pacer.

A lot has been attributed to the pitch in Chennai, where MI have played all their matches. MI batters have, in the past, been used to playing on batting-friendly pitch of the Wankhede Stadium.

Boult admitted that the pitch at Chennai's MA Chidambaram Stadium has been tough to bat on.

"The middle-order has been a key part of Mumbai Indians team. But things haven't gone to plan as yet. We have to appreciate that it is a very hard wicket to go out there and try boundaries," said Boult.