Arsenal were knocked out of the Champions League by Wolfsburg in the quarter-finals last seasonArsenal's hopes of reaching the Women's Champions League group stage are in the balance after a late Ajax equaliser in Tuesday's qualifier first leg.
Having fought back from a goal down, Arsenal conceded late on as Netherlands international Romee Leuchter scored a tap-in to level the tie at 2-2.
Substitute Katie McCabe then had a winning goal chalked off for offside.
Jonas Eidevall's team must win in Amsterdam next week to guarantee a group stage place.
A draw would take the qualifier to extra time and potentially a penalty shootout.
Leuchter opened the scoring at Meadow Park for Ajax after 17 minutes before a Stina Blackstenius strike levelled the scores just six minutes later.
Blackstenius, who also scored in Friday's 4-0 WSL victory against Brighton, scored with a volley after Rafaelle's header rebounded off the crossbar and fell to the Swedish forward.
Following a scrappy first half for the home side, Arsenal went ahead after the break when captain Kim Little calmly slotted home from the penalty spot after Beth Mead was fouled by Soraya Verhoeve.
Despite having the better chances, the Gunners fell foul to scrappy defending and failed to clear their lines as Leuchter claimed her second goal of the evening seven minutes from full-time.
Line-ups
Arsenal Women
Formation 4-2-3-1
1Zinsberger
16Maritz6Williamson2Carvalho Souza7Catley
10Little13Wälti
9Mead11Miedema17Hurtig
25Blackstenius
1Zinsberger16Maritz6Williamson2Carvalho Souza7Catley10Little13Wälti9Mead11Miedema17HurtigSubstituted forFoordat 58'minutes25BlacksteniusSubstituted forMcCabeat 75'minutesSubstitutes
3Wubben-Moy5Beattie8Nobbs12Maanum15McCabe18Marckese19Foord26Wienroither59Agyemang61Earl62ReidAjax Women
Formation 4-1-4-1
1Kop
2van der Most26Kardinaal4Doorn5Verhoeve
8Spitse
15Grant10Noordam23Pelova11Weerden
7Leuchter
1Kop2van der MostBooked at 64mins26Kardinaal4DoornBooked at 69mins5VerhoeveBooked at 55mins8Spitse15GrantSubstituted forBakkerat 90+2'minutes10Noordam23Pelova11WeerdenSubstituted forHoekstraat 62'minutes7Leuchter
