The deal will see Rivals carry a link to Lastminute.com on the navigation bar of all Rivals' websites, which include football, Formula 1 and rugby, as well as marketing on the website of Rivals Digital Media, parent of Rivals.
In return, Lastminute's sports homepage will carry a link to Rivals.net and Rivals branding leading Lastminute customers to the sports site.
Both companies will run competitions on the Rivals.net website.
Carl Lyons, head of UK marketing for Lastminute.com, said: "Lastminute.com has a terrific range of sports offers, and by working with Rivals, the UK's number one sports sites, we'll be making them available to more fans than ever before."
Meanwhile, Rivals.net parent Rivals Digital Media has hired Elizabeth Ryan as marketing manager from Midnight Communications, where she managed the sports site's PR.
Ryan has worked at Midnight since November 2001 when it merged with the company she had been working for, Flapjack Communications, since 1999.
She was quickly promoted to the position of senior account manager from account manager, where she was responsible for Thinknatural.com, Greenfingers and Estreet. She took on responsibility for the Rivals account in January.
As marketing manager for Rivals, Ryan will be responsible for creating, negotiating and implementing national marketing partnerships with other brands. She will also be in charge of Rivals' internal PR.
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