‘Boots’ captured the WBA and WBO154-pound world titles with a seventh-round stoppage of Xander Zayas on June 27 and quickly targeted Fundora as one of the opponents he wants next. Reports have since linked the two sides to ongoing negotiations for a possible November or December unification bout.

Shields praised Ennis’ victory over Zayas but said Fundora presents a completely different challenge because of his size and reach.

“Right now, at 154 pounds, he is the man,” said Shields to Fight Hub TV. “A big challenge for him will be Fundora. Fundora is a big challenge for anybody because of how long he is and his height, but Boots has enough in his arsenal, I feel, to beat Fundora, but he has got to be very, very smart.”

Shields pointed to moments in the Zayas fight where Ennis was caught clean and said those openings could be far more dangerous against the WBC champion.

“He can’t make the same mistakes that he made, getting hit with that straight jab and that right against Zayas. He can’t do that with Fundora. Cannot. Will not. He cannot do that,” Shields said. “Also, he cannot do that fighting on wobbly legs either.”

She also questioned Ennis’ decision to continue exchanging after being hurt.

“The only thing that he did wrong, for me, was fighting after that. Him fighting on wobbly legs, he should have moved around, jabbed, whatever. Be smart,” said Shields.

Fundora last fought on March 28, stopping former welterweight champion Keith Thurman in six rounds to retain his WBC junior middleweight title.

Ennis now holds the WBA, WBO and Ring Magazine championships after defeating Zayas, making a four-belt unification one of the biggest fights available in the division. Josh Kelly, meanwhile, is scheduled to defend his IBF title against Caoimhin Agyarko on July 25 in Saudi Arabia.