A second string Arsenal side beat first division West Bromwich Albion 2-0 and Bolton Wanderers edged Southampton 1-0 after extra time to reach the League Cup semi-finals on Tuesday.
Nigerian Nwankwo Kanu gave Arsenal a 25th minute lead and French strike partner Jeremie Aliadiere was gifted the other after a howler by West Brom goalkeeper Russell Hoult in the 57th minute.
Danish striker Henrik Pedersen grabbed the winner for Bolton with just five minutes left of extra time at the Reebok Stadium in the night's other quarter-final.
Though Arsenal finished up as comfortable winners, they led a charmed life in the first half as two penalty appeals against defender Martin Keown were dismissed by referee Matt Messias, West Brom midfielder James O'Connor had a header disallowed for offside and team mate Neil Clement hit the bar.
Arsenal took their only chance when Lauren's deflected cross was met with a powerful header by Kanu, Hoult parried but the Nigerian snapped up the loose ball from point blank range.
West Brom squandered further chances after the break before Hoult collected a simple backpass from Danish defender Thomas Gaardsoe, made a complete hash of his attempt to pass the ball on and allowed Aliadiere to intercept and rifle home.
"The experience we had in the side got us through but as well for the young players it was a great experience," manager Arsene Wenger told Sky Sports.
West Brom boss Gary Megson said: "The first goal we gave away was awful defending...and the last thing we needed was to concede a second goal, and in the manner we did."
Bolton had the lion's share of their first half but Southampton, FA Cup finalists last season, stepped up a gear after the break as chances fell at both ends.
But the matchwinner was once again Pedersen, whose last-minute cross on Saturday became an own goal by Chelsea defender John Terry in Bolton's shock 2-1 away victory.
Bolton manager Sam Allardyce said: "It's a fantastic result. Four years ago, we were in the semi-finals and lost to Tranmere. Let's try and make sure this time round we go all the way."
League Cup action continues on Wednesday when Aston Villa host Chelsea and Tottenham Hotspur entertain Middlesbrough.
The final is on February 29 at Cardiff's Millennium Stadium.