Index/match To Get Single Value

I have 2 spreadsheets with

Spreadsheet #1 All Vendor Transactions
Column D Column F Column V
Vendor Name Invoice Number Check Number
ABC 123 ?

Spreadsheet #2 Checks 1st QTR 2007
Column B Column D Column E
Vendor Name Invoice Number Check Number
ABC 123 99777
DEF 246 96504
XYZ 123 98654

I need to get Checks 1st QTR 2007!E1 Check number into All Vendor Transactions!V1

I could have done a VLOOKUP, but many of the values in Checks 1st QTR 2007!D1:59999 are duplicates as different vendors use the same invoice numbers. For various reasons,

I can't just use the Checks spreadsheets from each quarter.

I tried to use Index/match but kept getting my formula wrong.