The 61-year-old refused to say whether the team is better with a true No.9, while insisting he will play to win against Croatia in their last Group C game
A Fernando Torres double either side of the interval plus second-half goals from David Silva and Cesc Fabregas saw the European champions cruise to an emphatic win against Giovanni Trapattoni's side, who have been eliminated from the tournament.
Despite the hefty scoreline, Del Bosque rejected the notion that Spain had an easy match and noted that his players were at their best.
"We played well, regardless of everything that was done by Ireland, who were great on the pitch and in the stands," he told Tele5.
"We can be proud to have seen our best game against an opponent who refused to give up.
"We are strong and competing well."
The 61-year-old coach had come under intense scrutiny after leaving Torres on the bench for Spain's match against Italy and instead handing Fabregas the start.
"We pick our players for them to score," Del Bosque noted. "I know football well, I am not a novice. I know that I have to be prepared for criticism.
"The players feel just as comfortable with or without a No.9. They have no preference for Torres, [Alvaro] Negredo, [Fernando] Llorente or Fabregas."
A draw by two goals or more against Croatia on Monday would automatically eliminate Italy from the tournament, but Del Bosque has ruled out the possibility of making a deal with Slaven Bilic's side.
"We will prepare for that match to win," he insisted.