Goals from Britt Assombalonga and Jonny Howson ensured Boro are guaranteed to finish in either fifth or sixth position, setting up a play-off semi-final against either Cardiff, Fulham or Aston Villa.
They have to travel to Portman Road first and Pulis will use next Sunday’s game to make sure his players are in peak shape.
The Middlesbrough boss said: “We’re delighted that we’re now in the play-offs. Now it’s a case of looking forward to the Ipswich game and then going on from there.
“One or two players might need a rest and one or two players might be taken out of the Ipswich game. Alternatively I might go with the same team.
“I’ll have a good look at it next week and have a good chat with the boys and see where they are. Then we’ll look forward to those play-off games.
“The most important thing is that we’re right when we turn up here for the play-offs. The Ipswich game is important because it’s the next game and anyone who knows me as a man or a manager will know that every game I go into I want to win. But it’s about finding the right balance and concentrating on what is really important for us.”
Millwall still have a mathematical chance of making the play-offs, but it would need a remarkable sequence of events for them to overhaul Derby and Preston on the final day of the season.
Middlesbrough: Randolph, Shotton, Ayala, Gibson, Friend, Howson, Clayton, Besic, Traore, Assombalonga, Downing. Unused substitutes: Konstantopoulos, Da Silva, Leadbitter, Bamford, Cranie, Fry, Harrison.
Millwall: Archer, Romeo, Hutchinson, Cooper, Meredith, Wallace, Tunnicliffe, Williams, Marshall, Gregory, Morison. Unused substitutes: McLaughlin, Thompson, Onyedinma, Ferguson, Martin, Elliott, O’Brien.
Referee: P Tierney (Lancashire).