Taken from the wiki about the Suez Crisis of the 50s...
"Despite this convention, the strategic importance of the Suez Canal and its control were proven during the Russo-Japanese War of 1904–1905, after Japan and Britain entered into a separate bilateral agreement. Following the Japanese surprise attack on the Russian Pacific Fleet based at Port Arthur the Russians sent reinforcements from their fleet in the Baltic Sea. The British denied the Russian fleet use of the canal and forced it to steam around the entire continent of Africa, giving the Japanese forces time to solidify their position in the Far East."
How did this affect relations between Russians and the British. Why would they become allies 10 years later during WW1? I assume it was just a de facto alliance since they both happened to be fighting Germany by then?
The British denied the Russian fleet use of the canal
Part of the Russian battle fleet did transit the Suez Canal. The battleships Sissoi Velikie and Navarin, 3 cruisers and several smaller vessels and transports took the shortcut through the canal and met up with the main battle fleet in Madagascar. They transited the canal with the full knowledge of the British and were escorted by HMS Hermione.
(source: "The Tsars Last Armada", Constantine Pleshakov, pgs 111, 156-157)