Steven Taylor had not played a competitive game since August because of a hamstring injury, while Chiek Tiote might have left the club for Shanghai Shenhua last month.
Newcastle created more than enough chances to win the game long before the final whistle, but had to tough it out through a final five minutes which McClaren later admitted felt like 'five hours'.
The Magpies thought they had taken the lead through Tiote's 29th-minute screamer, only for referee Lee Mason to disallow it for offside after consulting his assistant, much to the annoyance of the home crowd and the Ivory Coast international.
Steve McClaren said with a smile: 'Tiote gets one goal every five years, so it is a bit disappointing to chalk that one off.'
Asked if the win had dragged the Baggies back into the relegation fight - they are currently five points better off than McClaren's men - the Newcastle boss said: 'I honestly don't look around, I just look at what we're doing.
'I'm not setting targets, but our next game is Chelsea, that's going to be tough, but we have just got to keep going forward, getting people fit and making sure consistently we put in performances like that.'