Steven Gerrard says he is at his "lowest" since joining Rangers after their 1-0 Scottish Cup quarter-final loss to Hearts
Oliver Bozanic's goal saw Rangers knocked out at the quarter-final stage of this competition for the second season in a row.
Rangers reached the Europa League last-16 on Wednesday after beating Braga 1-0 in Portugal, but Gerrard says he is disappointed that his side could not replicate that performance on Saturday night.
He said: "I'm very disappointed. It's the lowest I've felt since I've come to the club by a long way. The performance was nowhere near good enough.
"On Thursday, I was the proudest man in Europe by a long way because to a man the players were outstanding.
"Everything we've worked on for nearly two years, I could see it. I was proud as punch. It was an incredible performance.
"Today, for 90 minutes, I didn't recognise anything so I'm feeling really, really low and disappointed."
Without Alfredo Morelos due to a breach of club discipline, Saturday's loss means Rangers look set to extend their run without a major domestic trophy to nine years.
"I'm not sure we realised the importance of this game and the opportunity we had to go to Hampden," Gerrard added.
"It seems when we're the underdog and there's not much pressure, we're fantastic.
"When there's expectation to go to a tricky place to win, we have problems."
The former Liverpool midfielder signed a contract extension until 2024 in December, having led Rangers to their highest points total since returning to the Scottish Premiership in 2016 in his first campaign at the club last season.
But Gerrard hinted he will now assess his future, questioning his players' attitude after the defeat at Tynecastle.
"The plan was to have a day off tomorrow," he said. "I need to think hard about where we're at as a group.
"I need to do some real serious thinking over the next 24 and 48 hours.
"I'm feeling pain right now. I want to win here, I'm desperate to win here. Looking from the side today, I didn't get the impression that the feeling amongst my players was the same.
"I'm not doubting myself. Me and my staff have given these players absolutely everything for 20 months and held their hand on and off the pitch.
"We've improved everything for them but it's tough when every other performance you feel the way you feel. I need to analyse myself for sure."