Den [[30. januar]] [[2010]] blev Diaz mester i weltervægt i organisationen [[Strikeforce]] efter at have besejret [[Marius Žaromskis]] via knockout på [[Strikeforce: Miami]].<ref>{{Cite web |url=http://mmaweekly.com/diaz-wins-welterweight-belt-kos-zaromskis-in-1st-rd-2 |title=DIAZ WINS WELTERWEIGHT BELT, KO’S ZAROMSKIS IN 1ST RD |access-date=10. april 2011 |format= |work=mmaweekly.com}}</ref> Diaz vandt sin 10. kamp i træk og forsvarede sin Strikeforce-titel for tredje gang da han besejrede [[Paul Daley]] i hovedkampen på [[Strikeforce: Diaz vs. Daley]] den [[9. april]] [[2011]].<ref>{{Cite web|url=http://mmajunkie.com/news/23181/strikeforce-diaz-vs-daley-results.mma |title="Strikeforce: Diaz vs. Daley" results: Diaz survives scare, stops Daley in one-round thriller |access-date=10. april 2011 |format= |work=mmajunkie.com |archive-url=https://archive.today/20120525024047/http://mmajunkie.com/news/23181/strikeforce-diaz-vs-daley-results.mma |archive-date=25. maj 2012 }}</ref>
Levende_personer Sport