So I took all the 2009 marathons for which I could find a confirmed half-marathon split - essentially you had to go through in 1:03 or under to make the IAAF's half-marathon Top List in '09 - and ordered them by split times.
The only negative splits came at Rotterdam.
-0:47 James Kwambai Kenya 1:02:37 / 1:01:50 2:04:27 2nd Rotterdam
-0:45 Duncan Kibet Kenya 1:02:36 / 1:01:51 2:04:27 1st Rotterdam
-0:10 Abel Kirui Kenya 1:02:37 / 1:02:27 2:05:04 3rd Rotterdam
+0:13 Vincent Kipruto Kenya 1:02:47 / 1:03:00 2:05:47 1st Paris
+0:22 Gilbert Yegon Kenya 1:02:58 / 1:03:20 2:06:18 1st Amsterdam
+0:24 Abderrahim Goumri Morocco 1:02:50 / 1:03:14 2:06:04 2nd Chicago
+0:41 Bazu Worku Ethiopia 1:02:47 / 1:03:28 2:06:15 2nd Paris
+0:45 Elijah Keitany Kenya 1:02:58 / 1:03:43 2:06:41 2nd Amsterdam
+0:48 David Kemboi Kenya 1:02:49 / 1:03:37 2:06:26 3rd Paris
+0:56 Yemane Tsegay Ethiopia 1:02:47 / 1:03:43 2:06:30 4th Paris
+1:00 Patrick Makau Kenya 1:02:37 / 1:03:37 2:06:14 4th Rotterdam
+1:04 Paul Biwott Kenya 1:02:59 / 1:04:03 2:07:02 3rd Amsterdam
+1:14 Rachid Kisri Morocco 1:02:47 / 1:04:01 2:06:48 5th Paris
+1:17 David Mandago Kenya 1:02:48 / 1:04:05 2:06:53 6th Paris
+1:39 Samuel Wanjiru Kenya 1:02:01 / 1:03:40 2:05:41 1st Chicago
+1:45 Teferi Wodajo Ethiopia 1:03:00 / 1:04:45 2:07:45 4th Amsterdam
+1:46 Nicholas Kipkorir Kenya 1:03:00 / 1:04:46 2:07:46 5th Amsterdam
+1:55 Jonathan Kipkorir Kenya 1:02:48 / 1:04:43 2:07:31 7th Paris
+2:06 Vincent Kipruto Kenya 1:02:01 / 1:04:07 2:06:08 3rd Chicago
+2:24 Deriba Merga Ethiopia 1:02:44 / 1:05:08 2:07:52 1st Houston
+2:33 Shadrack Kiplagat Kenya 1:02:49 / 1:05:22 2:08:11 8th Paris
+2:38 Haile Gebrselassie Ethiopia 1:01:45 / 1:04:23 2:06:08 1st Berlin
+3:02 Daniel Too Kenya 1:02:48 / 1:05:50 2:08:38 10th Paris
+3:03 Richard Limo Kenya 1:02:50 / 1:05:53 2:08:43 5th Chicago
+3:04 Charles Munyeki Kenya 1:02:01 / 1:05:05 2:07:06 4th Chicago
+3:07 Abraham Chelanga Kenya 1:02:48 / 1:05:55 2:08:43 11th Paris
+3:34 Getu Feleke Ethiopia 1:02:59 / 1:06:33 2:09:32 8th Amsterdam
+3:37 Francis Kibiwott Kenya 1:02:48 / 1:06:25 2:09:13 12th Paris
+3:44 Jackson Kipkoech Kenya 1:02:37 / 1:06:21 2:08:58 5th Rotterdam
+4:03 Alfred Kering Kenya 1:02:38 / 1:06:41 2:09:19 6th Rotterdam
+4:24 Tesfaye Tola Ethiopia 1:02:59 / 1:07:23 2:10:22 9th Amsterdam
+4:41 Mikhail Lemaev Russia 1:03:00 / 1:07:41 2:10:41 15th Paris
+4:42 Robert Kipchumba Kenya 1:02:37 / 1:07:19 2:09:56 8th Rotterdam
+4:52 Alex Kirui Kenya 1:02:48 / 1:07:40 2:10:28 13th Paris
+4:55 Richard Limo Kenya 1:02:37 / 1:07:32 2:10:09 9th Rotterdam
+5:01 James Theuri France 1:02:49 / 1:07:50 2:10:39 14th Paris
+5:14 Deriba Deme Ethiopia 1:02:48 / 1:08:02 2:10:50 16th Paris
+5:29 Philemon Gitia Kenya 1:02:48 / 1:08:17 2:11:05 17th Paris
+6:40 Charles Kibiwott Kenya 1:03:00 / 1:09:40 2:12:40 12th Amsterdam
+7:01 Isaac Macharia Kenya 1:02:04 / 1:09:05 2:11:09 7th Chicago
+7:01 Robert Kipchumba Kenya 1:03:00 / 1:10:01 2:13:01 14th Amsterdam
+7:15 Dieudonné Disi Rwanda 1:02:48 / 1:10:03 2:12:51 18th Paris
+7:42 Kidane Gemechu Ethiopia 1:02:48 / 1:10:30 2:13:18 19th Paris
+10:07 Tekesete Nekatibebe Ethiopia 1:02:48 / 1:12:55 2:15:43 21st Paris
+11:08 Tadese Tola Ethiopia 1:02:20 / 1:13:28 2:15:48 10th Chicago
+11:23 Tesfaye Bekele Ethiopia 1:03:00 / 1:14:23 2:17:23 17th Amsterdam
+11:50 Benjamin Maiyo Kenya 1:02:24 / 1:14:14 2:16:38 11th Chicago