Giovanni van Bronckhorst believes James Sands’ red card proved pivotal in their 3-0 Champions League defeat by Napoli at Ibrox.
The Gers defender was sent off for conceding a penalty in the second half for a foul on Giovanni Simeone, after being booked minutes earlier.
Returning goalkeeper Allan McGregor brilliantly saved Piotr Zielinski’s first penalty, from which Matteo Politano scored the rebound, and his second attempt after a lengthy VAR check decided the spot-kick had to be retaken for encroachment.
However, another Napoli penalty arrived when Rangers left-back Borna Barisic handled in the box and this time Politano found the bottom corner.
Giacomo Raspadori added a second with five minutes remaining and fellow substitute Tanguy Ndombele grabbed a third in added time to leave Rangers with no points from their first two Group A games.
Van Bronckhorst said: “Until the red card we gave Napoli a really tough game.
“We were organised, good in the game and players were giving everything to get a good result.
“We created chances to open the scoring and it was a nice battle to see, but of course with the sending off we knew it was going to be difficult.
“Allan saved the penalty twice which was fantastic but the first goal we conceded made me change the way we were playing because we need to attack and you know you are going to get more space, so in the end I think the 3-0 defeat did not reflect the difference in quality.”
Defender Connor Goldson also believes the sending off was “100 per cent” the turning point in the game as he looked towards the cinch Premiership game against Dundee United in Saturday.
He told BT Sport: “It’s hard. The spaces started opening up.
“Even at 1-0 we tried to give it a go and we had attacking players on the pitch.
“But there was even more spaces and we gave another two goals away.
“Listen it’s hard, it’s tough to take. We’re in a tricky patch at the moment but we need to give that same effort and same belief on Saturday.
“Hopefully that will give us a win and get us back on track.”
Napoli boss Luciano Spalletti said: “After two missed penalties it was important that we kept going.
“They started really strong with their fans as we expected but instead of shrinking we reacted I felt.
“I thought it was a balanced game at a lot of points but we didn’t change, we never stopped pressing them and I want to thank everybody. It was another good game for me to be on the bench.”