Rangers manager Mark Warburton has celebrated his side's title success and says he wants four or five new players to compete in the Premiership next season.

A 1-0 win over Dumbarton at Ibrox sealed Championship success and automatic promotion and with the Petrofac Cup final and Scottish Cup semi-final against Celtic still to come he aims to build on his side's achievements.

Rangers had passed up the opportunity to seal the league win last weekend but completed the job against the Sons and Warburton said that there were signs his side were vulnerable. However, he said moves had already been made to strengthen for life in the top flight.

"If we drop our standards, we get punished," he said. "You've seen it this season. If we're off par, below par, we get hurt and that can't happen.

"It can't happen when you've got 50,000 at Hampden [for the Petrofac Cup final] and the following week [against Celtic].

"If we can prepare well, train hard and focus we'll be ok.

"It's a good group of players, we'll add to it in the summer and the work has begun on that front.

"If we can add the right recruitment, four or five players, we'll be in a good place."

The manager, who arrived at Ibrox last summer with former Rangers captain David Weir as his assistant, reflected on the title win and said it was the only acceptable outcome for the club.

After failing to be promoted through the play-offs last year, the Championship title and automatic promotion was the number one priority for the club this season and the former Brentford boss said he wanted to build on the momentum gained by the title success.

"We knew what we had to do," he said. "There was no grey area.

"This year it was clear, we had to get the club back into the top flight. That was very, very clear to us.

"We had 11 players come in, 16 go out and they've adjusted, adapted and displayed a work ethic and commitment that is great for David, myself and the staff.

"I'm delighted for the fans after what they've been through," he added. "It's great for the club to get back in the top tier.

"And for the players, there was a really clear directive about what we had to do this season so to have dealt with the weight of expectation and delivered as they have done, all credit to them.

"I'm delighted for the fans and the players."