Pakistan took a decisive 3-0 lead in the five match series against the visitors at Lahore with a 42-run victory last Tuesday.
"They [Bangladesh players] have to pull up their socks if they want to extend their international careers," Whatmore said Wednesday.
Bangladesh top order batsmen have failed to give their side a strong start with Mohammad Ashraful failing miserably in three innings as opener with the scores of 0, 3 and 0.
Pakistan captain Inzamam-ul-Haq said Bangladesh has showed tremendous signs of improvement, but the pressure of chasing over five runs-an-over was always difficult for the visitors.
"It's always difficult to chase over 250 if a team loses early wickets and that's the main reason that Bangladesh has struggled in the one-day series," Inzamam said.
Inzamam predicted his team would not make the Bangladesh team's task any easier for the fourth one-dayer.
"We are playing well as a unit and I see no reason why we should not continue the winning sequence going," he said.
Inzamam has so far won all three one-day tosses against Bangladesh captain Khaled Mahmud and on each occasion he preferred to bat first.
All the top order batsmen had scored runs with Yasir Hameed and Yousuf Youhana scoring centuries in Pakistan's 137-run and 74-run victories in the first two one-day internationals respectively.
Pakistan speedster Mohammad Sami is set to make a comeback against Bangladesh in the day-night match.
Sami missed Pakistan's 3-0 victory in the test series against Bangladesh due to ankle injury which he sustained while representing Kent in the English county championship in August this year.
* Pakistan: Mohammad Hafeez, Imran Nazir, Yasir Hameed, Inzamam-ul-Haq (captain), Yousuf Youhana, Junaid Zia, Kamran Akmal (wicketkeeper), Shabbir Ahmad, Umer Gul, Shoaib Malik, Abdul Razzaq, Younis Khan, Mohammad Sami, Danish Kaneria, Salman Butt
* Bangladesh: Khaled Mahmud (captain), Hannan Sarkar, Habibul Bashar, Sanwar Hossain, Mohammad Ashraful, Razin Saleh, Alok Kapali, Mohammad Rafique, Khaled Mashud, Tapash Baisya, Alamgir Kabir, Mashrafe Bin Murtaza, Mushfiqur Rehman, Hasibul Hossain and Tushar Imran.
* Umpires: Russell Tiffin, Zimbabwe, Aleem Dar, Pakistan, television umpire: Asad Rauf, Pakistan, match referee: Mike Procter, South Africa