Mertesacker, who started his first Premier League game since April 2016 at Vicarage Road, headed the Gunners ahead minutes before half-time as he easily rose above the former Manchester United midfielder from a corner.
A controversial penalty decision and a late winner from Cleverley saw Arsene Wenger’s side throw away their lead, though Crooks still saw enough from Mertesacker to name him in his BBC Sport team of the week.
While Crooks was impressed with the form from the Arsenal captain, he wasn’t exactly convinced by the Hornets’ marking.
“I was shocked to see Mertesacker starting the game,” Crooks said. “And with the captain's armband.
“It was like rolling back the years to the days when he used to appear regularly in my team of the week!
“This defender is clearly very clever. He never overextends himself and appears a model professional.
“His headed goal against Watford was like taking candy from a baby - what a mismatch asking Tom Cleverley to mark Mertesacker on a set-piece. That's like asking Ryan Giggs to fight Mike Tyson!”