New Delhi: A pat on the back by none other than International Boxing Association president Ching Kuo Wu came as a shot in the arm as five Indian boxers geared up for the Asian Olympic Qualifiers semifinals in Astana, Kazakhstan on Wednesday.

Of the five in fray, only Vijender Singh (75kg) is assured of a London berth so far as his category has four slots on offer. The 26-year-old Olympic and World Championship bronze medallist will be appearing in his third Olympics -- a first for an Indian boxer.

Shiva Thapa (56kg) and Sumit Sangwan (81kg) need to win their respective semifinals to be assured of a ticket to London, while Manpreet Singh (91kg) and Paramjeet Samota (+91kg) have to go all the way and clinch a gold to make it to the Olympics.

Shiva and Sumit can qualify for London even if they don't win tomorrow provided their respective opponents go on to clinch gold medals as their categories have three slots each up for grabs.

Shiva will face Japan's Satoshi Simizu, Manpreet will fight it out with Iran's Ali Mazaheri, while Sumit will be up against Jordan's Ihab Almatdault in the semifinals.

Samota will be competing against Syria's Soumar Ghosoun in his first bout of the event as he got a bye in the semis, while Vijender will take on Asian and Youth Olympics bronze medallist Nursahat Pazziyev.

As they geared up for the big battle, the Indian contingent's performance drew the attention of Wu, who is in Astana, and he put in a word of praise for the country's pugilists.

"The AIBA President has congratulated the Indian contingent and praised its performance," national coach Gurbax Singh Sandhu said from Astana.

"I was attending a meeting of Asian Boxing Confederation where Dr Wu was also there and he specifically asked about where the Indian representative was and came down to praise my boys' performance. He said he was impressed with whatever he has seen of the boys," Sandhu added.

Wu has reason to praise as the Indians have put up a tremendous performance so far. Of the six who came to the event, five are in the semifinals as only Suranjoy Singh (52kg) lost in the preliminaries.

The 18-year-old Shiva beat a former Olympic silver-medallist -- Thailand's Worapoj Petchkoom -- to make it to the semifinals, while the 19-year-old Sumit, playing his first senior international event, has also performed exceptionally well.

"All my boys have defeated top boxers and they are in high spirits. The upcoming bouts are going to be very tough but I am positive and I expect all five of them to reach the finals," said Sandhu.

"The way they have performed is fantastic. Vijender came back from being down, Manpreet managed to simply outclass his rival after being down four points in his bout. They way Shiva defeated an Olympic medallist, it has all been just exceptional," Sandhu said.

But there a tinge of disappointment as well at Suranjoy's early exit as the Commonwealth Games gold-medallist was considered a strong contender for Olympic qualification.

"It is sad but it was just not his day and he lost to a better boxer. That's all to it," said Sandhu.

Four Indian boxers -- L Devendro Singh (49kg), Jai Bhagwan (60kg), Manoj Kumar (64kg) and Vikas Krishan (69kg) -- had already booked their berths in the Olympics in last year's World Championships.