Andrew Johnson's 35th-minute goal was enough to give Palace three vital points that lifted them out of the Premiership relegation zone, but Benitez must be regretting his decision to rest some of his key players.
The gifted Spanish playmaker Xabi Alonso - who Benitez claimed was injured - was not even on the bench, and John Arne Riise only came on as a second-half substitute. Luis Garcia had a thigh injury and Igor Biscan was rested. Liverpool also missed the chance to close the gap on Everton - who could only draw 1-1 at home to Birmingham - in the race to qualify for next season's Champions' League. They are now four points behind their Merseyside neighbours.
Benitez was clearly upset by Palace's physical approach. "We wanted to win the game but sometimes it is not possible to play football," he said. "Football is football and is similar everywhere but I have not seen many games like this in other countries.
"Watch the match on television and analyse the game. Look at the three challenges on Milan Baros and judge for yourselves."
The Czech Republic striker, was forced to hobble off shortly before half-time after some rough treatment from the Palace defenders and Benitez does not yet know whether if he will be fit to face Chelsea.
The Palace assistant manager, Kit Symons, dismissed suggestions that the Eagles had played on the edge of the rules in order to gain victory. "Look at the bookings count," he said. "Five of their players were booked, and only two of ours."
Palace are now a point clear of West Bromwich Albion - who have a match in hand - and two above Southampton, who face their local rivals Portsmouth today. Iain Dowie's men have a home match against Southampton on 7 May, sandwiched between trips to Newcastle and Charlton, whom they face on the final day of the Premiership campaign.
Symons added: "The fight for survival. will be about which team can hold its nerve, and which team is willing to play football when the going is tough."
Mindful of the biggest match of Liverpool's season at Stamford Bridge, Benitez made four changes to his starting line-up. The captain, Steven Gerrard, was brought back into the side along with Anthony Le Tallec, Mauricio Pellegrino and John Welsh. Alonso and Luis Garcia should be available to face Chelsea.
The Palace manager, Iain Dowie, also made four changes, with Danny Granville, Tony Popovic, Aki Riihilahti and Tom Soares all recalled. The changes seemed to work as Palace displayed an excellent attitude, high work-rate and the displays of Johnson, central defender Fitz Hall and midfielder Michael Hughes were superb.
Although Liverpool settled into the game better than their hosts, Palace seemed to be the more threatening. In the 27th minute Hall played a superb crossfield pass to release Johnson, whose clever reverse ball found Granville, but the left-back could not find the finish to match his run and Jerzy Dudek saved easily. At the other end, Le Tallec found Baros with a clever pass, but Gonzalo Sorondo was alert to the danger and made a perfectly timed tackle for Palace.
The home side took the lead in the 35th minute. Jamie Carragher headed Granville's cross clear, but when Routledge volleyed the ball back into the danger zone from the right it was Johnson who reacted quickest to head the ball into Dudek's bottom-right corner.
Palace began the second half as dynamically as they had ended the first, and Liverpool were lucky not to fall further behind. Sami Hyypia and Pellegrino made a hash of Johnson's low cross, but Soares - perhaps surprised that the ball had reached him - shot high and wide.
Liverpool responded by switching to a 4-4-2 formation after Fernando Morientes' header had been saved by Gabor Kiraly, Benitez sending on Riise for Pellegrino. After a quiet first half, Gerrard's influence grew as his side came forward in search of an equaliser.
The England midfielder showed his ability with a clever pass for Morientes in the 71st minute, and the Spain striker was denied only by a superb tackle from Popovic. Eight minutes later, a raking pass from Gerrard picked out the Liverpool substitute Djibril Cissé on the right corner of the penalty area, but the Frenchman's volley was easily stopped by Kiraly.
The Hungary goalkeeper then kept his side in front with a fantastic save from Gerrard's well-struck effort from 20 yards following Morientes' knock-down. At the end, Palace sometimes defended with eight men. But they defended well.