Giovanni van Bronckhorst’s men fell to a 2-0 defeat in their Champions League third qualifying round tie with Belgian’s Royale Union Saint-Gilloise.
They conceded in either half, including a dubious penalty awarded with 15 minutes to go when Connor Goldson was penalised for a handball.
On Sky Sports, he labelled the display “slow, lethargic”, while pinpointing the two players who the team need to help turn around the deficit in the return leg at Ibrox next week.
"If there was anyone who underestimated the Belgians in Scotland tonight they have had a wake up call," Boyd said. “They can perform at this level.
"But for Rangers, you've got to be doing better than you've done tonight. They were slow, lethargic and looked as if there was no energy about them. It's similar to the first half on Saturday [in the 2-1 win at Livingston].
“To be honest they are really lucky to come away with a 2-0. Rangers going back to Ibrox with a 2-0 defeat is probably the best they could have hoped for at this moment in time. Yes, the second one was a little bit dubious. As soon as that goal went in it became an uphill challenge for Rangers.
"They're going to need that Ibrox crowd again. The fans can turn up and get behind you, but the players are going to have to put on a far, far better performance than they did tonight. They'll hopefully have Ryan Kent back, who has been one of the star performers in Europe, and Alfredo Morelos. They looked a pale shadow of the team we saw in Europe last season, that's for sure."
‘Heck of a lot of work’
Meanwhile, Ally McCoist was left baffled by the penalty award, labelling it a “mental" decision.
He also, however, noted the position the team find themselves in and the performance they will have to deliver at Ibrox before they are even to consider facing Monaco or PSV Eindhoven in the play-off round.
“We went down to the bottom of the Scottish leagues and have only played European football in the last two or three years," the Rangers legend told talkSPORT. “But you’ve got to say on last night’s performance, there’s a heck of a lot of work to be done before they can start thinking about Monaco or Eindhoven, that’s for sure.”
Rangers boss Van Bronckhorst admitted the team were “lucky” they only lost 2-0 and how they need “to change it around big time”.
"We were sloppy, losing a lot of balls, not winning the duels and they became better and better and we didn’t react well after that," he said.
"We were never really in the game, a lot of mistakes, giving many transition moments away defensively. It was the basics of the game – quick passing, the control, the awareness of where the pressure comes from.”