Mumbai - Mumbai Indians' star off-spinner Harbhajan Singh said that it was difficult to explain why his side began their Indian Premier league (IPL) campaign with a home loss against debutants Rising Pune Supergiants. An all-round Rising Pune Supergiants thrashed Mumbai by nine wickets in the IPL-9 opener on Saturday at the Wankhede Stadium here. Batting first, Mumbai were restricted to only 121/8 in 20 overs, thanks to a superb bowling performance by Pune. In reply, riding on Ajinkya Rahane's unbeaten 66, Pune chased down the target comfortably, while losing just one wicket, posting 126/1 in 14.4 overs. "I wish I know the reason, we would like to have won the first game and started on a good note. We tried our best whatever total we had on board. Hopefully from next game onwards we will get the result we were looking for," Harbhajan said at post-match press conference here. "It should not be like five games MI don't play well and then we suddenly wake up and start playing well. Hopefully, it will happen in Kolkata." Harbhajan, who remained unbeaten on 45, said Mumbai's batting must improve. "We did not bat as well as we should have. It was a tough game for us. Mumbai wicket is probably the best to bat on. Poor shot selection made us where we landed. We just need to work on our game a bit more," the 35-year-old said. The offie, who claimed the only wicket to fall, defended skipper Rohit Sharma's decision to bat after winning the toss. "It was Rohit's decision to bat first. I go by it. As a team member we need to back his decision and go with whatever he feels is right. Maybe it was about less pressure on batsmen while batting first. Lots of teams like to chase here," he said. Mumbai next face Kolkata Knight Riders on April 13 at the Eden Gardens and Harbhajan said that after looking at the Kolkata wicket there could be minor changes in the side. He hoped they will earn their first win of the season. "Depending on the wicket we get in Kolkata, there could be some changes. I am not one to select the team, but I am always there to give my feedback about what combination should be. As a senior player they obviously ask me what I feel and I give my suggestion what combination should be," Harbhajan added.