Boro’s win leaves them level on points with sixth-placed Derby County, who beat Bristol City and have a game in hand, to be played against Swansea City on Wednesday.
But Pulis’s side did what they needed to stay in contention as Lewis Wing’s equaliser and Britt Assombalonga’s 39th-minute penalty turned Saturday’s match in their favour.
Wing’s goal cancelled out Danny Loader’s brilliant opener in the 11th minute for Reading and ensured he marked his return to action in style after recovering from hernia surgery.
Pulis said: “We can’t do anything about Derby.
“They’ve got three points against Bristol, now they play Swansea; what we’ve done is kept the pressure on.
“If we hadn’t have won that would have been it. We’ve won so there’s pressure on them going into the next two games. Football is a funny old game.
“Reading scored a great goal, a great strike to beat Darren Randolph from that distance. Darren is best goalkeeper in the league, so to beat him from that distance is top drawer.
“But the reaction was fantastic. At half-time we’re coming in and I know we’ve scored two, but you’re wondering how we haven’t scored three, four or five.
“I kept Wingy on, I should have brought him off. I apologised to him because he was tired, but I wanted him to get that 90 minutes. I’ve tried to keep it as quiet as I could (that he would play). We could have got him involved a game earlier, but I was concerned about him coming back and pulling a muscle or something.
“I always had this game in mind, but I wanted to keep it as quiet as I could.”
Despite losing at the Riverside, Reading, for whom 18-year-old Loader scored his first senior goal, are now mathematically safe following Rotherham’s defeat at West Brom.
“They had already effectively secured their place in the Championship for another season before the trip to the north east, but it is now guaranteed.
Middlesbrough: Randolph, McNair, Flint,Shotton, Howson, Wing, Mikel, Besic (Clayton 68), Saville, Fletcher (Tavernier 81), Assombalonga (Hugill 86). Unused substitutes: Konstantopoulos, Downing, Wood-Gordon, Gestede.
Reading: Martinez, Yiadom, Miazga, Moore, Gunter (Olise 74), Rinomhota, Baker, Ejaria, Loader, Baldock (Harriott 63), McCleary (Barrett 74). Unused substitutes: Walker, Ezatolahi, Kelly,McIntyre.
Referee: John Brooks (Leicestershire).